Version 4.2.1, July 2009
Added string->unreadable-symbol and symbol-interned?
Added syntax-local-lift-provide
Added syntax-local-lift-values-expression
Added identifier-prune-lexical-context and quote-syntax/prune

Version 4.2, May 2009
Changed visiting of modules at phase N to happen only when compilation
 at phase N starts
Changed expander to detect a reaname transformer and install a
 free-identifier=? syntax-object equivalence
Changed provide to convert an exported rename transformer to its
 free-identifier=? target
Added 'not-free-identifier=? syntax property to disable free-identifier=? 
 propagation through a rename transformer
Added prop:rename-transformer and prop:set!-transformer
Fixed scheme/local so that local syntax bindings are visible to later
 local definitions
Changed current-process-milliseconds to accept a thread argument
Added hash-hash-key?, hash-ref!
Added in-sequences, in-cycle

Version 4.1.5, March 2009
Allow infix notation for prefab structure literals
Change quasiquote so that unquote works in value positions of #hash
Change read-syntax to represent #hash value forms as syntax
Added bitwise-bit-field

Version 4.1.4, January 2009
Changed memory accounting to bias charges to parent instead of children
Changed function contracts to preserve tail recursion in many cases
Added scheme/package, scheme/splicing, ffi/objc
Added exception-backtrace support for x86_84+JIT
Added equal?/recur
Added equal<%> and interface* to scheme/class
Added procedure-rename
Added extra arguments to call-with-continuation-prompt
Added extra argument to raise-syntax-error
Added compile-context-preservation-enabled
Added syntax-local-lift-require
Added internal-definition-context-seal, which must be used on an
 internal-definition context before it's part of a fully expanded form
Added syntax-local-make-delta-introducer
Changed make-rename-transformer to accept an introducer argument that
 cooperates with syntax-local-make-delta-introducer
Added internal-defininition-context?
Added identifier-remove-from-defininition-context

Version 4.1.3, November 2008
Changed scheme to re-export scheme/port
In scheme/port: added 
Added call-with-immediate-continuation-mark
In scheme/port: added port->string, port->bytes, port->lines
 port->bytes-lines, display-lines, [call-]with-input-from-{string,bytes},
 and [call-]with-output-to-{string,bytes}
In scheme/file: added file->string, file->bytes, file->lines,
 file->value, file->bytes-lines, write-to-file, display-to-file,
 and display-lines-to-file
Added variable-reference? and empty #%variable-reference form
Extended continuation-marks to work on a thread argument

Version 4.1.2, October 2008
Changed binding of identifiers introduced by unit signatures
 to take into account the signature use's context
Added make-syntax-delta-introducer
Changed continuation-marks to accept a thread argument
Added eqv-based hash tables
Added hash-update and hash-update!
Changed -X and -S to complete directory relative to pwd, and
 changed -S to add after main collects

Version 4.1.1, October 2008
Added read-language
Added module-compiled-language-info, module->language-info,
 and 'module-language property support

Version 4.1, August 2008
Changed namespaces to have a base phase; for example, calling
 eval at compile-time uses a phase-1 namespace
Added logging facilities: make-logger, etc.
Added "inheritance" to structure type properties, and change
 prop:procedure from scheme/base to better support keywords
Added bitwise-bit-set?
Added in-value

Version 4.0, June 2008
>> See MzScheme_4.txt

Version 372, December 2007
Added syntax-local-lift-context
Added #lang
Added require-for-label, provide-for-syntax, provide-for-label,
 identifier-label-binding, module-label-identifier=?

Version 371, August 2007
Added hash-table-iterate-{first,next,key,value}
Added keyword<?
Added make-derived-parameter
Added make-sibling-inspector
Added graph? argument to read[-syntax]/recursive
Added read-accept-infix-dot
Changed #!<space> and #!/ to general comment forms
Added continuation?
Added continuation-prompt-tag?
Inside MzScheme: GC_{malloc,free}_immobile_box
foreign.ss: added {malloc,free}-immobile-box

Version 370, May 2007
Memory management:
 Default build uses 3m instead of CGC
 Added custodian boxes and custodian-memory-accounting-available?
 Added initial custodian argument to custodian-require-memory
Exceptions:
 Removed current-exception-handler and initial-exception-handler
 Added uncaught-exception-handler
 Default error escape handler aborts to default continuation
  tag with the void procedure
 Added call-with-exception-handler
 Changed read-eval-print-loop and the default load handler to wrap
  each evaluation with a prompt and with #%top-interaction
 Changed top-level begin to insert a prompt around each sub-expression
  except the last
 Added #%top-interaction and #%expression
 Changed make-exn to automatically convert a mutable message string
  to an immutable string
Units:
 New unit system provided by MzLib's "unit.ss"
Ports and pathnames:
 Added prop:input-port and prop:output-port
 Added support for manipulating filesystem paths that work on 
  other platforms
 Added string->path-element and path-element->string
 Changed path->directory-path, simplify-path, and split-path to include
  a trailing path separator even when the result would be a directory
  path without it
 Changed simplify-path for Windows paths to replace / with \
 Changed current-directory to apply path->directory-path to given paths
 Added reset?, start-, and end-index arguments to get-output-bytes
 Added port-closed?
 Added optional argument to tcp-addresses to get port numbers
Syntax and loading:
 Default load handler enables #reader (even when not reading a module)
 Added module-path-index-resolve
 Added syntax-local-expand-expression
 Changed dyanmic-require to expand requests for exported syntax
  bindings
 Added an argument to syntax-local-certifier indicating whether the
  generated procedure attaches active or inactive certificates
 Changed macro expansion of bound identifiers so that `local-expand'
  works with an empty stop list
 Module top-level enforces initial categorization of expressions
  versus other forms
 Changed H-expression parsing to represent angle brackets specially
Misc:
 Changed print-struct default to #t instead of #f
 Added parameterize*
 Added 'gc and 'so-suffix flags for system-type
 Added vector->values
 Changed char-whitespace? to produce #t for #\u0085
 Added -p, -P, and -Q command-line options
 Added procedure-struct-type?
 Added system-idle-evt
 Fixed mzc --exe to work with C-implemented extension modules
MzLib:
 serialize.ss: Path includes the path's convention
 foreign.ss: Added ptr-add, memmove, memcpy, and memset
 runtime-paths.ss: Cooperates with mzc --exe
Inside MzScheme:
 Use SCHEME_INPUT_PORTP() instead of SCHEME_INPORTP()
     SCHEME_OUTPUT_PORTP() instead of SCHEME_OUTPORTP()
     scheme_input_port_record() instead of cast to Scheme_Input_Port*
     scheme_output_port_record() instead of cast to Scheme_Output_Port*
 Added scheme_set_type_equality() with help from Dimitris Vyzovitis
 Added XFORM_START_SKIP, etc.

Version 360, November 2006
Continuations:
 Added delimited continuations: call-with-continuation-prompt,
  call-with-composable-continuation, etc.
 Changed call-with-escape-continuation so that its argument is
  no longer applied in tail position (reverses a change in v350)
Regexps:
 Added case-insensitive mode, multi-line mode, lookahead, lookbehind, 
  non-backtracking, and conditionals to regexp language
 Added pregexp, byte-pregexp, and #px..., which includes numeric
  quantifiers, backreferences char classes, and Unicode predicates
 Added regexp-match?, pregexp?, and byte-pregexp?
 Improved [p]regexp performance
Filesystem:
 Unix and Mac OS X: Changed path operations to use "./~..." as an
  encoding for a relative path "~..."
 Changed simplify-path to always normalize path separators,
  preserve syntactic directoryness, and remove \\?\ from
  Windows paths when possible
 Added path-element->bytes and bytes->path-element
 Changed make-file-or-es active                                                 Version 4.2.1, July 2009
Added string->unreadable-symbol and symbol-interned?
Added syntax-local-lift-provide
Added syntax-local-lift-values-expression
Added identifier-prune-lexical-context and quote-syntax/prune

Version 4.2, May 2009
Changed visiting of modules at phase N to happen only when compilation
 at phase N starts
Changed expander to detect a reaname transformer and install a
 free-identifier=? syntax-object equivalence
Changed provide to convert an exported rename transformer to its
 free-identifier=? target
Added 'not-free-identifier=? syntax property to disable free-identifier=? 
 propagation through a rename transformer
Added prop:rename-transformer and prop:set!-transformer
Fixed scheme/local so that local syntax bindings are visible to later
 local definitions
Changed current-process-milliseconds to accept a thread argument
Added hash-hash-key?, hash-ref!
Added in-sequences, in-cycle

Version 4.1.5, March 2009
Allow infix notation for prefab structure literals
Change quasiquote so that unquote works in value positions of #hash
Change read-syntax to represent #hash value forms as syntax
Added bitwise-bit-field

Version 4.1.4, January 2009
Changed memory accounting to bias charges to parent instead of children
Changed function contracts to preserve tail recursion in many cases
Added scheme/package, scheme/splicing, ffi/objc
Added exception-backtrace support for x86_84+JIT
Added equal?/recur
Added equal<%> and interface* to scheme/class
Added procedure-rename
Added extra arguments to call-with-continuation-prompt
Added extra argument to raise-syntax-error
Added compile-context-preservation-enabled
Added syntax-local-lift-require
Added internal-definition-context-seal, which must be used on an
 internal-definition context before it's part of a fully expanded form
Added syntax-local-make-delta-introducer
Changed make-rename-transformer to accept an introducer argument that
 cooperates with syntax-local-make-delta-introducer
Added internal-defininition-context?
Added identifier-remove-from-defininition-context

Version 4.1.3, November 2008
Changed scheme to re-export scheme/port
In scheme/port: added 
Added call-with-immediate-continuation-mark
In scheme/port: added port->string, port->bytes, port->lines
 port->bytes-lines, display-lines, [call-]with-input-from-{string,bytes},
 and [call-]with-output-to-{string,bytes}
In scheme/file: added file->string, file->bytes, file->lines,
 file->value, file->bytes-lines, write-to-file, display-to-file,
 and display-lines-to-file
Added variable-reference? and empty #%variable-reference form
Extended continuation-marks to work on a thread argument

Version 4.1.2, October 2008
Changed binding of identifiers introduced by unit signatures
 to take into account the signature use's context
Added make-syntax-delta-introducer
Changed continuation-marks to accept a thread argument
Added eqv-based hash tables
Added hash-update and hash-update!
Changed -X and -S to complete directory relative to pwd, and
 changed -S to add after main collects

Version 4.1.1, October 2008
Added read-language
Added module-compiled-language-info, module->language-info,
 and 'module-language property support

Version 4.1, August 2008
Changed namespaces to have a base phase; for example, calling
 eval at compile-time uses a phase-1 namespace
Added logging facilities: make-logger, etc.
Added "inheritance" to structure type properties, and change
 prop:procedure from scheme/base to better support keywords
Added bitwise-bit-set?
Added in-value

Version 4.0, June 2008
>> See MzScheme_4.txt

Version 372, December 2007
Added syntax-local-lift-context
Added #lang
Added require-for-label, provide-for-syntax, provide-for-label,
 identifier-label-binding, module-label-identifier=?

Version 371, August 2007
Added hash-table-iterate-{first,next,key,value}
Added keyword<?
Added make-derived-parameter
Added make-sibling-inspector
Added graph? argument to read[-syntax]/recursive
Added read-accept-infix-dot
Changed #!<space> and #!/ to general comment forms
Added continuation?
Added continuation-prompt-tag?
Inside MzScheme: GC_{malloc,free}_immobile_box
foreign.ss: added {malloc,free}-immobile-box

Version 370, May 2007
Memory management:
 Default build uses 3m instead of CGC
 Added custodian boxes and custodian-memory-accounting-available?
 Added initial custodian argument to custodian-require-memory
Exceptions:
 Removed current-exception-handler and initial-exception-handler
 Added uncaught-exception-handler
 Default error escape handler aborts to default continuation
  tag with the void procedure
 Added call-with-exception-handler
 Changed read-eval-print-loop and the default load handler to wrap
  each evaluation with a prompt and with #%top-interaction
 Changed top-level begin to insert a prompt around each sub-expression
  except the last
 Added #%top-interaction and #%expression
 Changed make-exn to automatically convert a mutable message string
  to an immutable string
Units:
 New unit system provided by MzLib's "unit.ss"
Ports and pathnames:
 Added prop:input-port and prop:output-port
 Added support for manipulating filesystem paths that work on 
  other platforms
 Added string->path-element and path-element->string
 Changed path->directory-path, simplify-path, and split-path to include
  a trailing path separator even when the result would be a directory
  path without it
 Changed simplify-path for Windows paths to replace / with \
 Changed current-directory to apply path->directory-path to given paths
 Added reset?, start-, and end-index arguments to get-output-bytes
 Added port-closed?
 Added optional argument to tcp-addresses to get port numbers
Syntax and loading:
 Default load handler enables #reader (even when not reading a module)
 Added module-path-index-resolve
 Added syntax-local-expand-expression
 Changed dyanmic-require to expand requests for exported syntax
  bindings
 Added an argument to syntax-local-certifier indicating whether the
  generated procedure attaches active or inactive certificates
 Changed macro expansion of bound identifiers so that `local-expand'
  works with an empty stop list
 Module top-level enforces initial categorization of expressions
  versus other forms
 Changed H-expression parsing to represent angle brackets specially
Misc:
 Changed print-struct default to #t instead of #f
 Added parameterize*
 Added 'gc and 'so-suffix flags for system-type
 Added vector->values
 Changed char-whitespace? to produce #t for #\u0085
 Added -p, -P, and -Q command-line options
 Added procedure-struct-type?
 Added system-idle-evt
 Fixed mzc --exe to work with C-implemented extension modules
MzLib:
 serialize.ss: Path includes the path's convention
 foreign.ss: Added ptr-add, memmove, memcpy, and memset
 runtime-paths.ss: Cooperates with mzc --exe
Inside MzScheme:
 Use SCHEME_INPUT_PORTP() instead of SCHEME_INPORTP()
     SCHEME_OUTPUT_PORTP() instead of SCHEME_OUTPORTP()
     scheme_input_port_record() instead of cast to Scheme_Input_Port*
     scheme_output_port_record() instead of cast to Scheme_Output_Port*
 Added scheme_set_type_equality() with help from Dimitris Vyzovitis
 Added XFORM_START_SKIP, etc.

Version 360, November 2006
Continuations:
 Added delimited continuations: call-with-continuation-prompt,
  call-with-composable-continuation, etc.
 Changed call-with-escape-continuation so that its argument is
  no longer applied in tail position (reverses a change in v350)
Regexps:
 Added case-insensitive mode, multi-line mode, lookahead, lookbehind, 
  non-backtracking, and conditionals to regexp language
 Added pregexp, byte-pregexp, and #px..., which includes numeric
  quantifiers, backreferences char classes, and Unicode predicates
 Added regexp-match?, pregexp?, and byte-pregexp?
 Improved [p]regexp performance
Filesystem:
 Unix and Mac OS X: Changed path operations to use "./~..." as an
  encoding for a relative path "~..."
 Changed simplify-path to always normalize path separators,
  preserve syntactic directoryness, and remove \\?\ from
  Windows paths when possible
 Added path-element->bytes and bytes->path-element
 Changed make-file-or-es active                                                 Version 4.2.1, July 2009
Added string->unreadable-symbol and symbol-interned?
Added syntax-local-lift-provide
Added syntax-local-lift-values-expression
Added identifier-prune-lexical-context and quote-syntax/prune

Version 4.2, May 2009
Changed visiting of modules at phase N to happen only when compilation
 at phase N starts
Changed expander to detect a reaname transformer and install a
 free-identifier=? syntax-object equivalence
Changed provide to convert an exported rename transformer to its
 free-identifier=? target
Added 'not-free-identifier=? syntax property to disable free-identifier=? 
 propagation through a rename transformer
Added prop:rename-transformer and prop:set!-transformer
Fixed scheme/local so that local syntax bindings are visible to later
 local definitions
Changed current-process-milliseconds to accept a thread argument
Added hash-hash-key?, hash-ref!
Added in-sequences, in-cycle

Version 4.1.5, March 2009
Allow infix notation for prefab structure literals
Change quasiquote so that unquote works in value positions of #hash
Change read-syntax to represent #hash value forms as syntax
Added bitwise-bit-field

Version 4.1.4, January 2009
Changed memory accounting to bias charges to parent instead of children
Changed function contracts to preserve tail recursion in many cases
Added scheme/package, scheme/splicing, ffi/objc
Added exception-backtrace support for x86_84+JIT
Added equal?/recur
Added equal<%> and interface* to scheme/class
Added procedure-rename
Added extra arguments to call-with-continuation-prompt
Added extra argument to raise-syntax-error
Added compile-context-preservation-enabled
Added syntax-local-lift-require
Added internal-definition-context-seal, which must be used on an
 internal-definition context before it's part of a fully expanded form
Added syntax-local-make-delta-introducer
Changed make-rename-transformer to accept an introducer argument that
 cooperates with syntax-local-make-delta-introducer
Added internal-defininition-context?
Added identifier-remove-from-defininition-context

Version 4.1.3, November 2008
Changed scheme to re-export scheme/port
In scheme/port: added 
Added call-with-immediate-continuation-mark
In scheme/port: added port->string, port->bytes, port->lines
 port->bytes-lines, display-lines, [call-]with-input-from-{string,bytes},
 and [call-]with-output-to-{string,bytes}
In scheme/file: added file->string, file->bytes, file->lines,
 file->value, file->bytes-lines, write-to-file, display-to-file,
 and display-lines-to-file
Added variable-reference? and empty #%variable-reference form
Extended continuation-marks to work on a thread argument

Version 4.1.2, October 2008
Changed binding of identifiers introduced by unit signatures
 to take into account the signature use's context
Added make-syntax-delta-introducer
Changed continuation-marks to accept a thread argument
Added eqv-based hash tables
Added hash-update and hash-update!
Changed -X and -S to complete directory relative to pwd, and
 changed -S to add after main collects

Version 4.1.1, October 2008
Added read-language
Added module-compiled-language-info, module->language-info,
 and 'module-language property support

Version 4.1, August 2008
Changed namespaces to have a base phase; for example, calling
 eval at compile-time uses a phase-1 namespace
Added logging facilities: make-logger, etc.
Added "inheritance" to structure type properties, and change
 prop:procedure from scheme/base to better support keywords
Added bitwise-bit-set?
Added in-value

Version 4.0, June 2008
>> See MzScheme_4.txt

Version 372, December 2007
Added syntax-local-lift-context
Added #lang
Added require-for-label, provide-for-syntax, provide-for-label,
 identifier-label-binding, module-label-identifier=?

Version 371, August 2007
Added hash-table-iterate-{first,next,key,value}
Added keyword<?
Added make-derived-parameter
Added make-sibling-inspector
Added graph? argument to read[-syntax]/recursive
Added read-accept-infix-dot
Changed #!<space> and #!/ to general comment forms
Added continuation?
Added continuation-prompt-tag?
Inside MzScheme: GC_{malloc,free}_immobile_box
foreign.ss: added {malloc,free}-immobile-box

Version 370, May 2007
Memory management:
 Default build uses 3m instead of CGC
 Added custodian boxes and custodian-memory-accounting-available?
 Added initial custodian argument to custodian-require-memory
Exceptions:
 Removed current-exception-handler and initial-exception-handler
 Added uncaught-exception-handler
 Default error escape handler aborts to default continuation
  tag with the void procedure
 Added call-with-exception-handler
 Changed read-eval-print-loop and the default load handler to wrap
  each evaluation with a prompt and with #%top-interaction
 Changed top-level begin to insert a prompt around each sub-expression
  except the last
 Added #%top-interaction and #%expression
 Changed make-exn to automatically convert a mutable message string
  to an immutable string
Units:
 New unit system provided by MzLib's "unit.ss"
Ports and pathnames:
 Added prop:input-port and prop:output-port
 Added support for manipulating filesystem paths that work on 
  other platforms
 Added string->path-element and path-element->string
 Changed path->directory-path, simplify-path, and split-path to include
  a trailing path separator even when the result would be a directory
  path without it
 Changed simplify-path for Windows paths to replace / with \
 Changed current-directory to apply path->directory-path to given paths
 Added reset?, start-, and end-index arguments to get-output-bytes
 Added port-closed?
 Added optional argument to tcp-addresses to get port numbers
Syntax and loading:
 Default load handler enables #reader (even when not reading a module)
 Added module-path-index-resolve
 Added syntax-local-expand-expression
 Changed dyanmic-require to expand requests for exported syntax
  bindings
 Added an argument to syntax-local-certifier indicating whether the
  generated procedure attaches active or inactive certificates
 Changed macro expansion of bound identifiers so that `local-expand'
  works with an empty stop list
 Module top-level enforces initial categorization of expressions
  versus other forms
 Changed H-expression parsing to represent angle brackets specially
Misc:
 Changed print-struct default to #t instead of #f
 Added parameterize*
 Added 'gc and 'so-suffix flags for system-type
 Added vector->values
 Changed char-whitespace? to produce #t for #\u0085
 Added -p, -P, and -Q command-line options
 Added procedure-struct-type?
 Added system-idle-evt
 Fixed mzc --exe to work with C-implemented extension modules
MzLib:
 serialize.ss: Path includes the path's convention
 foreign.ss: Added ptr-add, memmove, memcpy, and memset
 runtime-paths.ss: Cooperates with mzc --exe
Inside MzScheme:
 Use SCHEME_INPUT_PORTP() instead of SCHEME_INPORTP()
     SCHEME_OUTPUT_PORTP() instead of SCHEME_OUTPORTP()
     scheme_input_port_record() instead of cast to Scheme_Input_Port*
     scheme_output_port_record() instead of cast to Scheme_Output_Port*
 Added scheme_set_type_equality() with help from Dimitris Vyzovitis
 Added XFORM_START_SKIP, etc.

Version 360, November 2006
Continuations:
 Added delimited continuations: call-with-continuation-prompt,
  call-with-composable-continuation, etc.
 Changed call-with-escape-continuation so that its argument is
  no longer applied in tail position (reverses a change in v350)
Regexps:
 Added case-insensitive mode, multi-line mode, lookahead, lookbehind, 
  non-backtracking, and conditionals to regexp language
 Added pregexp, byte-pregexp, and #px..., which includes numeric
  quantifiers, backreferences char classes, and Unicode predicates
 Added regexp-match?, pregexp?, and byte-pregexp?
 Improved [p]regexp performance
Filesystem:
 Unix and Mac OS X: Changed path operations to use "./~..." as an
  encoding for a relative path "~..."
 Changed simplify-path to always normalize path separators,
  preserve syntactic directoryness, and remove \\?\ from
  Windows paths when possible
 Added path-element->bytes and bytes->path-element
 Changed make-file-or-es active                                                 Version 4.2.1, July 2009
Added string->unreadable-symbol and symbol-interned?
Added syntax-local-lift-provide
Added syntax-local-lift-values-expression
Added identifier-prune-lexical-context and quote-syntax/prune

Version 4.2, May 2009
Changed visiting of modules at phase N to happen only when compilation
 at phase N starts
Changed expander to detect a reaname transformer and install a
 free-identifier=? syntax-object equivalence
Changed provide to convert an exported rename transformer to its
 free-identifier=? target
Added 'not-free-identifier=? syntax property to disable free-identifier=? 
 propagation through a rename transformer
Added prop:rename-transformer and prop:set!-transformer
Fixed scheme/local so that local syntax bindings are visible to later
 local definitions
Changed current-process-milliseconds to accept a thread argument
Added hash-hash-key?, hash-ref!
Added in-sequences, in-cycle

Version 4.1.5, March 2009
Allow infix notation for prefab structure literals
Change quasiquote so that unquote works in value positions of #hash
Change read-syntax to represent #hash value forms as syntax
Added bitwise-bit-field

Version 4.1.4, January 2009
Changed memory accounting to bias charges to parent instead of children
Changed function contracts to preserve tail recursion in many cases
Added scheme/package, scheme/splicing, ffi/objc
Added exception-backtrace support for x86_84+JIT
Added equal?/recur
Added equal<%> and interface* to scheme/class
Added procedure-rename
Added extra arguments to call-with-continuation-prompt
Added extra argument to raise-syntax-error
Added compile-context-preservation-enabled
Added syntax-local-lift-require
Added internal-definition-context-seal, which must be used on an
 internal-definition context before it's part of a fully expanded form
Added syntax-local-make-delta-introducer
Changed make-rename-transformer to accept an introducer argument that
 cooperates with syntax-local-make-delta-introducer
Added internal-defininition-context?
Added identifier-remove-from-defininition-context

Version 4.1.3, November 2008
Changed scheme to re-export scheme/port
In scheme/port: added 
Added call-with-immediate-continuation-mark
In scheme/port: added port->string, port->bytes, port->lines
 port->bytes-lines, display-lines, [call-]with-input-from-{string,bytes},
 and [call-]with-output-to-{string,bytes}
In scheme/file: added file->string, file->bytes, file->lines,
 file->value, file->bytes-lines, write-to-file, display-to-file,
 and display-lines-to-file
Added variable-reference? and empty #%variable-reference form
Extended continuation-marks to work on a thread argument

Version 4.1.2, October 2008
Changed binding of identifiers introduced by unit signatures
 to take into account the signature use's context
Added make-syntax-delta-introducer
Changed continuation-marks to accept a thread argument
Added eqv-based hash tables
Added hash-update and hash-update!
Changed -X and -S to complete directory relative to pwd, and
 changed -S to add after main collects

Version 4.1.1, October 2008
Added read-language
Added module-compiled-language-info, module->language-info,
 and 'module-language property support

Version 4.1, August 2008
Changed namespaces to have a base phase; for example, calling
 eval at compile-time uses a phase-1 namespace
Added logging facilities: make-logger, etc.
Added "inheritance" to structure type properties, and change
 prop:procedure from scheme/base to better support keywords
Added bitwise-bit-set?
Added in-value

Version 4.0, June 2008
>> See MzScheme_4.txt

Version 372, December 2007
Added syntax-local-lift-context
Added #lang
Added require-for-label, provide-for-syntax, provide-for-label,
 identifier-label-binding, module-label-identifier=?

Version 371, August 2007
Added hash-table-iterate-{first,next,key,value}
Added keyword<?
Added make-derived-parameter
Added make-sibling-inspector
Added graph? argument to read[-syntax]/recursive
Added read-accept-infix-dot
Changed #!<space> and #!/ to general comment forms
Added continuation?
Added continuation-prompt-tag?
Inside MzScheme: GC_{malloc,free}_immobile_box
foreign.ss: added {malloc,free}-immobile-box

Version 370, May 2007
Memory management:
 Default build uses 3m instead of CGC
 Added custodian boxes and custodian-memory-accounting-available?
 Added initial custodian argument to custodian-require-memory
Exceptions:
 Removed current-exception-handler and initial-exception-handler
 Added uncaught-exception-handler
 Default error escape handler aborts to default continuation
  tag with the void procedure
 Added call-with-exception-handler
 Changed read-eval-print-loop and the default load handler to wrap
  each evaluation with a prompt and with #%top-interaction
 Changed top-level begin to insert a prompt around each sub-expression
  except the last
 Added #%top-interaction and #%expression
 Changed make-exn to automatically convert a mutable message string
  to an immutable string
Units:
 New unit system provided by MzLib's "unit.ss"
Ports and pathnames:
 Added prop:input-port and prop:output-port
 Added support for manipulating filesystem paths that work on 
  other platforms
 Added string->path-element and path-element->string
 Changed path->directory-path, simplify-path, and split-path to include
  a trailing path separator even when the result would be a directory
  path without it
 Changed simplify-path for Windows paths to replace / with \
 Changed current-directory to apply path->directory-path to given paths
 Added reset?, start-, and end-index arguments to get-output-bytes
 Added port-closed?
 Added optional argument to tcp-addresses to get port numbers
Syntax and loading:
 Default load handler enables #reader (even when not reading a module)
 Added module-path-index-resolve
 Added syntax-local-expand-expression
 Changed dyanmic-require to expand requests for exported syntax
  bindings
 Added an argument to syntax-local-certifier indicating whether the
  generated procedure attaches active or inactive certificates
 Changed macro expansion of bound identifiers so that `local-expand'
  works with an empty stop list
 Module top-level enforces initial categorization of expressions
  versus other forms
 Changed H-expression parsing to represent angle brackets specially
Misc:
 Changed print-struct default to #t instead of #f
 Added parameterize*
 Added 'gc and 'so-suffix flags for system-type
 Added vector->values
 Changed char-whitespace? to produce #t for #\u0085
 Added -p, -P, and -Q command-line options
 Added procedure-struct-type?
 Added system-idle-evt
 Fixed mzc --exe to work with C-implemented extension modules
MzLib:
 serialize.ss: Path includes the path's convention
 foreign.ss: Added ptr-add, memmove, memcpy, and memset
 runtime-paths.ss: Cooperates with mzc --exe
Inside MzScheme:
 Use SCHEME_INPUT_PORTP() instead of SCHEME_INPORTP()
     SCHEME_OUTPUT_PORTP() instead of SCHEME_OUTPORTP()
     scheme_input_port_record() instead of cast to Scheme_Input_Port*
     scheme_output_port_record() instead of cast to Scheme_Output_Port*
 Added scheme_set_type_equality() with help from Dimitris Vyzovitis
 Added XFORM_START_SKIP, etc.

Version 360, November 2006
Continuations:
 Added delimited continuations: call-with-continuation-prompt,
  call-with-composable-continuation, etc.
 Changed call-with-escape-continuation so that its argument is
  no longer applied in tail position (reverses a change in v350)
Regexps:
 Added case-insensitive mode, multi-line mode, lookahead, lookbehind, 
  non-backtracking, and conditionals to regexp language
 Added pregexp, byte-pregexp, and #px..., which includes numeric
  quantifiers, backreferences char classes, and Unicode predicates
 Added regexp-match?, pregexp?, and byte-pregexp?
 Improved [p]regexp performance
Filesystem:
 Unix and Mac OS X: Changed path operations to use "./~..." as an
  encoding for a relative path "~..."
 Changed simplify-path to always normalize path separators,
  preserve syntactic directoryness, and remove \\?\ from
  Windows paths when possible
 Added path-element->bytes and bytes->path-element
 Changed make-file-or-es active                                                 Version 4.2.1, July 2009
Added string->unreadable-symbol and symbol-interned?
Added syntax-local-lift-provide
Added syntax-local-lift-values-expression
Added identifier-prune-lexical-context and quote-syntax/prune

Version 4.2, May 2009
Changed visiting of modules at phase N to happen only when compilation
 at phase N starts
Changed expander to detect a reaname transformer and install a
 free-identifier=? syntax-object equivalence
Changed provide to convert an exported rename transformer to its
 free-identifier=? target
Added 'not-free-identifier=? syntax property to disable free-identifier=? 
 propagation through a rename transformer
Added prop:rename-transformer and prop:set!-transformer
Fixed scheme/local so that local syntax bindings are visible to later
 local definitions
Changed current-process-milliseconds to accept a thread argument
Added hash-hash-key?, hash-ref!
Added in-sequences, in-cycle

Version 4.1.5, March 2009
Allow infix notation for prefab structure literals
Change quasiquote so that unquote works in value positions of #hash
Change read-syntax to represent #hash value forms as syntax
Added bitwise-bit-field

Version 4.1.4, January 2009
Changed memory accounting to bias charges to parent instead of children
Changed function contracts to preserve tail recursion in many cases
Added scheme/package, scheme/splicing, ffi/objc
Added exception-backtrace support for x86_84+JIT
Added equal?/recur
Added equal<%> and interface* to scheme/class
Added procedure-rename
Added extra arguments to call-with-continuation-prompt
Added extra argument to raise-syntax-error
Added compile-context-preservation-enabled
Added syntax-local-lift-require
Added internal-definition-context-seal, which must be used on an
 internal-definition context before it's part of a fully expanded form
Added syntax-local-make-delta-introducer
Changed make-rename-transformer to accept an introducer argument that
 cooperates with syntax-local-make-delta-introducer
Added internal-defininition-context?
Added identifier-remove-from-defininition-context

Version 4.1.3, November 2008
Changed scheme to re-export scheme/port
In scheme/port: added 
Added call-with-immediate-continuation-mark
In scheme/port: added port->string, port->bytes, port->lines
 port->bytes-lines, display-lines, [call-]with-input-from-{string,bytes},
 and [call-]with-output-to-{string,bytes}
In scheme/file: added file->string, file->bytes, file->lines,
 file->value, file->bytes-lines, write-to-file, display-to-file,
 and display-lines-to-file
Added variable-reference? and empty #%variable-reference form
Extended continuation-marks to work on a thread argument

Version 4.1.2, October 2008
Changed binding of identifiers introduced by unit signatures
 to take into account the signature use's context
Added make-syntax-delta-introducer
Changed continuation-marks to accept a thread argument
Added eqv-based hash tables
Added hash-update and hash-update!
Changed -X and -S to complete directory relative to pwd, and
 changed -S to add after main collects

Version 4.1.1, October 2008
Added read-language
Added module-compiled-language-info, module->language-info,
 and 'module-language property support

Version 4.1, August 2008
Changed namespaces to have a base phase; for example, calling
 eval at compile-time uses a phase-1 namespace
Added logging facilities: make-logger, etc.
Added "inheritance" to structure type properties, and change
 prop:procedure from scheme/base to better support keywords
Added bitwise-bit-set?
Added in-value

Version 4.0, June 2008
>> See MzScheme_4.txt

Version 372, December 2007
Added syntax-local-lift-context
Added #lang
Added require-for-label, provide-for-syntax, provide-for-label,
 identifier-label-binding, module-label-identifier=?

Version 371, August 2007
Added hash-table-iterate-{first,next,key,value}
Added keyword<?
Added make-derived-parameter
Added make-sibling-inspector
Added graph? argument to read[-syntax]/recursive
Added read-accept-infix-dot
Changed #!<space> and #!/ to general comment forms
Added continuation?
Added continuation-prompt-tag?
Inside MzScheme: GC_{malloc,free}_immobile_box
foreign.ss: added {malloc,free}-immobile-box

Version 370, May 2007
Memory management:
 Default build uses 3m instead of CGC
 Added custodian boxes and custodian-memory-accounting-available?
 Added initial custodian argument to custodian-require-memory
Exceptions:
 Removed current-exception-handler and initial-exception-handler
 Added uncaught-exception-handler
 Default error escape handler aborts to default continuation
  tag with the void procedure
 Added call-with-exception-handler
 Changed read-eval-print-loop and the default load handler to wrap
  each evaluation with a prompt and with #%top-interaction
 Changed top-level begin to insert a prompt around each sub-expression
  except the last
 Added #%top-interaction and #%expression
 Changed make-exn to automatically convert a mutable message string
  to an immutable string
Units:
 New unit system provided by MzLib's "unit.ss"
Ports and pathnames:
 Added prop:input-port and prop:output-port
 Added support for manipulating filesystem paths that work on 
  other platforms
 Added string->path-element and path-element->string
 Changed path->directory-path, simplify-path, and split-path to include
  a trailing path separator even when the result would be a directory
  path without it
 Changed simplify-path for Windows paths to replace / with \
 Changed current-directory to apply path->directory-path to given paths
 Added reset?, start-, and end-index arguments to get-output-bytes
 Added port-closed?
 Added optional argument to tcp-addresses to get port numbers
Syntax and loading:
 Default load handler enables #reader (even when not reading a module)
 Added module-path-index-resolve
 Added syntax-local-expand-expression
 Changed dyanmic-require to expand requests for exported syntax
  bindings
 Added an argument to syntax-local-certifier indicating whether the
  generated procedure attaches active or inactive certificates
 Changed macro expansion of bound identifiers so that `local-expand'
  works with an empty stop list
 Module top-level enforces initial categorization of expressions
  versus other forms
 Changed H-expression parsing to represent angle brackets specially
Misc:
 Changed print-struct default to #t instead of #f
 Added parameterize*
 Added 'gc and 'so-suffix flags for system-type
 Added vector->values
 Changed char-whitespace? to produce #t for #\u0085
 Added -p, -P, and -Q command-line options
 Added procedure-struct-type?
 Added system-idle-evt
 Fixed mzc --exe to work with C-implemented extension modules
MzLib:
 serialize.ss: Path includes the path's convention
 foreign.ss: Added ptr-add, memmove, memcpy, and memset
 runtime-paths.ss: Cooperates with mzc --exe
Inside MzScheme:
 Use SCHEME_INPUT_PORTP() instead of SCHEME_INPORTP()
     SCHEME_OUTPUT_PORTP() instead of SCHEME_OUTPORTP()
     scheme_input_port_record() instead of cast to Scheme_Input_Port*
     scheme_output_port_record() instead of cast to Scheme_Output_Port*
 Added scheme_set_type_equality() with help from Dimitris Vyzovitis
 Added XFORM_START_SKIP, etc.

Version 360, November 2006
Continuations:
 Added delimited continuations: call-with-continuation-prompt,
  call-with-composable-continuation, etc.
 Changed call-with-escape-continuation so that its argument is
  no longer applied in tail position (reverses a change in v350)
Regexps:
 Added case-insensitive mode, multi-line mode, lookahead, lookbehind, 
  non-backtracking, and conditionals to regexp language
 Added pregexp, byte-pregexp, and #px..., which includes numeric
  quantifiers, backreferences char classes, and Unicode predicates
 Added regexp-match?, pregexp?, and byte-pregexp?
 Improved [p]regexp performance
Filesystem:
 Unix and Mac OS X: Changed path operations to use "./~..." as an
  encoding for a relative path "~..."
 Changed simplify-path to always normalize path separators,
  preserve syntactic directoryness, and remove \\?\ from
  Windows paths when possible
 Added path-element->bytes and bytes->path-element
 Changed make-file-or-es active                                                 Version 4.2.1, July 2009
Added string->unreadable-symbol and symbol-interned?
Added syntax-local-lift-provide
Added syntax-local-lift-values-expression
Added identifier-prune-lexical-context and quote-syntax/prune

Version 4.2, May 2009
Changed visiting of modules at phase N to happen only when compilation
 at phase N starts
Changed expander to detect a reaname transformer and install a
 free-identifier=? syntax-object equivalence
Changed provide to convert an exported rename transformer to its
 free-identifier=? target
Added 'not-free-identifier=? syntax property to disable free-identifier=? 
 propagation through a rename transformer
Added prop:rename-transformer and prop:set!-transformer
Fixed scheme/local so that local syntax bindings are visible to later
 local definitions
Changed current-process-milliseconds to accept a thread argument
Added hash-hash-key?, hash-ref!
Added in-sequences, in-cycle

Version 4.1.5, March 2009
Allow infix notation for prefab structure literals
Change quasiquote so that unquote works in value positions of #hash
Change read-syntax to represent #hash value forms as syntax
Added bitwise-bit-field

Version 4.1.4, January 2009
Changed memory accounting to bias charges to parent instead of children
Changed function contracts to preserve tail recursion in many cases
Added scheme/package, scheme/splicing, ffi/objc
Added exception-backtrace support for x86_84+JIT
Added equal?/recur
Added equal<%> and interface* to scheme/class
Added procedure-rename
Added extra arguments to call-with-continuation-prompt
Added extra argument to raise-syntax-error
Added compile-context-preservation-enabled
Added syntax-local-lift-require
Added internal-definition-context-seal, which must be used on an
 internal-definition context before it's part of a fully expanded form
Added syntax-local-make-delta-introducer
Changed make-rename-transformer to accept an introducer argument that
 cooperates with syntax-local-make-delta-introducer
Added internal-defininition-context?
Added identifier-remove-from-defininition-context

Version 4.1.3, November 2008
Changed scheme to re-export scheme/port
In scheme/port: added 
Added call-with-immediate-continuation-mark
In scheme/port: added port->string, port->bytes, port->lines
 port->bytes-lines, display-lines, [call-]with-input-from-{string,bytes},
 and [call-]with-output-to-{string,bytes}
In scheme/file: added file->string, file->bytes, file->lines,
 file->value, file->bytes-lines, write-to-file, display-to-file,
 and display-lines-to-file
Added variable-reference? and empty #%variable-reference form
Extended continuation-marks to work on a thread argument

Version 4.1.2, October 2008
Changed binding of identifiers introduced by unit signatures
 to take into account the signature use's context
Added make-syntax-delta-introducer
Changed continuation-marks to accept a thread argument
Added eqv-based hash tables
Added hash-update and hash-update!
Changed -X and -S to complete directory relative to pwd, and
 changed -S to add after main collects

Version 4.1.1, October 2008
Added read-language
Added module-compiled-language-info, module->language-info,
 and 'module-language property support

Version 4.1, August 2008
Changed namespaces to have a base phase; for example, calling
 eval at compile-time uses a phase-1 namespace
Added logging facilities: make-logger, etc.
Added "inheritance" to structure type properties, and change
 prop:procedure from scheme/base to better support keywords
Added bitwise-bit-set?
Added in-value

Version 4.0, June 2008
>> See MzScheme_4.txt

Version 372, December 2007
Added syntax-local-lift-context
Added #lang
Added require-for-label, provide-for-syntax, provide-for-label,
 identifier-label-binding, module-label-identifier=?

Version 371, August 2007
Added hash-table-iterate-{first,next,key,value}
Added keyword<?
Added make-derived-parameter
Added make-sibling-inspector
Added graph? argument to read[-syntax]/recursive
Added read-accept-infix-dot
Changed #!<space> and #!/ to general comment forms
Added continuation?
Added continuation-prompt-tag?
Inside MzScheme: GC_{malloc,free}_immobile_box
foreign.ss: added {malloc,free}-immobile-box

Version 370, May 2007
Memory management:
 Default build uses 3m instead of CGC
 Added custodian boxes and custodian-memory-accounting-available?
 Added initial custodian argument to custodian-require-memory
Exceptions:
 Removed current-exception-handler and initial-exception-handler
 Added uncaught-exception-handler
 Default error escape handler aborts to default continuation
  tag with the void procedure
 Added call-with-exception-handler
 Changed read-eval-print-loop and the default load handler to wrap
  each evaluation with a prompt and with #%top-interaction
 Changed top-level begin to insert a prompt around each sub-expression
  except the last
 Added #%top-interaction and #%expression
 Changed make-exn to automatically convert a mutable message string
  to an immutable string
Units:
 New unit system provided by MzLib's "unit.ss"
Ports and pathnames:
 Added prop:input-port and prop:output-port
 Added support for manipulating filesystem paths that work on 
  other platforms
 Added string->path-element and path-element->string
 Changed path->directory-path, simplify-path, and split-path to include
  a trailing path separator even when the result would be a directory
  path without it
 Changed simplify-path for Windows paths to replace / with \
 Changed current-directory to apply path->directory-path to given paths
 Added reset?, start-, and end-index arguments to get-output-bytes
 Added port-closed?
 Added optional argument to tcp-addresses to get port numbers
Syntax and loading:
 Default load handler enables #reader (even when not reading a module)
 Added module-path-index-resolve
 Added syntax-local-expand-expression
 Changed dyanmic-require to expand requests for exported syntax
  bindings
 Added an argument to syntax-local-certifier indicating whether the
  generated procedure attaches active or inactive certificates
 Changed macro expansion of bound identifiers so that `local-expand'
  works with an empty stop list
 Module top-level enforces initial categorization of expressions
  versus other forms
 Changed H-expression parsing to represent angle brackets specially
Misc:
 Changed print-struct default to #t instead of #f
 Added parameterize*
 Added 'gc and 'so-suffix flags for system-type
 Added vector->values
 Changed char-whitespace? to produce #t for #\u0085
 Added -p, -P, and -Q command-line options
 Added procedure-struct-type?
 Added system-idle-evt
 Fixed mzc --exe to work with C-implemented extension modules
MzLib:
 serialize.ss: Path includes the path's convention
 foreign.ss: Added ptr-add, memmove, memcpy, and memset
 runtime-paths.ss: Cooperates with mzc --exe
Inside MzScheme:
 Use SCHEME_INPUT_PORTP() instead of SCHEME_INPORTP()
     SCHEME_OUTPUT_PORTP() instead of SCHEME_OUTPORTP()
     scheme_input_port_record() instead of cast to Scheme_Input_Port*
     scheme_output_port_record() instead of cast to Scheme_Output_Port*
 Added scheme_set_type_equality() with help from Dimitris Vyzovitis
 Added XFORM_START_SKIP, etc.

Version 360, November 2006
Continuations:
 Added delimited continuations: call-with-continuation-prompt,
  call-with-composable-continuation, etc.
 Changed call-with-escape-continuation so that its argument is
  no longer applied in tail position (reverses a change in v350)
Regexps:
 Added case-insensitive mode, multi-line mode, lookahead, lookbehind, 
  non-backtracking, and conditionals to regexp language
 Added pregexp, byte-pregexp, and #px..., which includes numeric
  quantifiers, backreferences char classes, and Unicode predicates
 Added regexp-match?, pregexp?, and byte-pregexp?
 Improved [p]regexp performance
Filesystem:
 Unix and Mac OS X: Changed path operations to use "./~..." as an
  encoding for a relative path "~..."
 Changed simplify-path to always normalize path separators,
  preserve syntactic directoryness, and remove \\?\ from
  Windows paths when possible
 Added path-element->bytes and bytes->path-element
 Changed make-file-or-es active                                                 Version 4.2.1, July 2009
Added string->unreadable-symbol and symbol-interned?
Added syntax-local-lift-provide
Added syntax-local-lift-values-expression
Added identifier-prune-lexical-context and quote-syntax/prune

Version 4.2, May 2009
Changed visiting of modules at phase N to happen only when compilation
 at phase N starts
Changed expander to detect a reaname transformer and install a
 free-identifier=? syntax-object equivalence
Changed provide to convert an exported rename transformer to its
 free-identifier=? target
Added 'not-free-identifier=? syntax property to disable free-identifier=? 
 propagation through a rename transformer
Added prop:rename-transformer and prop:set!-transformer
Fixed scheme/local so that local syntax bindings are visible to later
 local definitions
Changed current-process-milliseconds to accept a thread argument
Added hash-hash-key?, hash-ref!
Added in-sequences, in-cycle

Version 4.1.5, March 2009
Allow infix notation for prefab structure literals
Change quasiquote so that unquote works in value positions of #hash
Change read-syntax to represent #hash value forms as syntax
Added bitwise-bit-field

Version 4.1.4, January 2009
Changed memory accounting to bias charges to parent instead of children
Changed function contracts to preserve tail recursion in many cases
Added scheme/package, scheme/splicing, ffi/objc
Added exception-backtrace support for x86_84+JIT
Added equal?/recur
Added equal<%> and interface* to scheme/class
Added procedure-rename
Added extra arguments to call-with-continuation-prompt
Added extra argument to raise-syntax-error
Added compile-context-preservation-enabled
Added syntax-local-lift-require
Added internal-definition-context-seal, which must be used on an
 internal-definition context before it's part of a fully expanded form
Added syntax-local-make-delta-introducer
Changed make-rename-transformer to accept an introducer argument that
 cooperates with syntax-local-make-delta-introducer
Added internal-defininition-context?
Added identifier-remove-from-defininition-context

Version 4.1.3, November 2008
Changed scheme to re-export scheme/port
In scheme/port: added 
Added call-with-immediate-continuation-mark
In scheme/port: added port->string, port->bytes, port->lines
 port->bytes-lines, display-lines, [call-]with-input-from-{string,bytes},
 and [call-]with-output-to-{string,bytes}
In scheme/file: added file->string, file->bytes, file->lines,
 file->value, file->bytes-lines, write-to-file, display-to-file,
 and display-lines-to-file
Added variable-reference? and empty #%variable-reference form
Extended continuation-marks to work on a thread argument

Version 4.1.2, October 2008
Changed binding of identifiers introduced by unit signatures
 to take into account the signature use's context
Added make-syntax-delta-introducer
Changed continuation-marks to accept a thread argument
Added eqv-based hash tables
Added hash-update and hash-update!
Changed -X and -S to complete directory relative to pwd, and
 changed -S to add after main collects

Version 4.1.1, October 2008
Added read-language
Added module-compiled-language-info, module->language-info,
 and 'module-language property support

Version 4.1, August 2008
Changed namespaces to have a base phase; for example, calling
 eval at compile-time uses a phase-1 namespace
Added logging facilities: make-logger, etc.
Added "inheritance" to structure type properties, and change
 prop:procedure from scheme/base to better support keywords
Added bitwise-bit-set?
Added in-value

Version 4.0, June 2008
>> See MzScheme_4.txt

Version 372, December 2007
Added syntax-local-lift-context
Added #lang
Added require-for-label, provide-for-syntax, provide-for-label,
 identifier-label-binding, module-label-identifier=?

Version 371, August 2007
Added hash-table-iterate-{first,next,key,value}
Added keyword<?
Added make-derived-parameter
Added make-sibling-inspector
Added graph? argument to read[-syntax]/recursive
Added read-accept-infix-dot
Changed #!<space> and #!/ to general comment forms
Added continuation?
Added continuation-prompt-tag?
Inside MzScheme: GC_{malloc,free}_immobile_box
foreign.ss: added {malloc,free}-immobile-box

Version 370, May 2007
Memory management:
 Default build uses 3m instead of CGC
 Added custodian boxes and custodian-memory-accounting-available?
 Added initial custodian argument to custodian-require-memory
Exceptions:
 Removed current-exception-handler and initial-exception-handler
 Added uncaught-exception-handler
 Default error escape handler aborts to default continuation
  tag with the void procedure
 Added call-with-exception-handler
 Changed read-eval-print-loop and the default load handler to wrap
  each evaluation with a prompt and with #%top-interaction
 Changed top-level begin to insert a prompt around each sub-expression
  except the last
 Added #%top-interaction and #%expression
 Changed make-exn to automatically convert a mutable message string
  to an immutable string
Units:
 New unit system provided by MzLib's "unit.ss"
Ports and pathnames:
 Added prop:input-port and prop:output-port
 Added support for manipulating filesystem paths that work on 
  other platforms
 Added string->path-element and path-element->string
 Changed path->directory-path, simplify-path, and split-path to include
  a trailing path separator even when the result would be a directory
  path without it
 Changed simplify-path for Windows paths to replace / with \
 Changed current-directory to apply path->directory-path to given paths
 Added reset?, start-, and end-index arguments to get-output-bytes
 Added port-closed?
 Added optional argument to tcp-addresses to get port numbers
Syntax and loading:
 Default load handler enables #reader (even when not reading a module)
 Added module-path-index-resolve
 Added syntax-local-expand-expression
 Changed dyanmic-require to expand requests for exported syntax
  bindings
 Added an argument to syntax-local-certifier indicating whether the
  generated procedure attaches active or inactive certificates
 Changed macro expansion of bound identifiers so that `local-expand'
  works with an empty stop list
 Module top-level enforces initial categorization of expressions
  versus other forms
 Changed H-expression parsing to represent angle brackets specially
Misc:
 Changed print-struct default to #t instead of #f
 Added parameterize*
 Added 'gc and 'so-suffix flags for system-type
 Added vector->values
 Changed char-whitespace? to produce #t for #\u0085
 Added -p, -P, and -Q command-line options
 Added procedure-struct-type?
 Added system-idle-evt
 Fixed mzc --exe to work with C-implemented extension modules
MzLib:
 serialize.ss: Path includes the path's convention
 foreign.ss: Added ptr-add, memmove, memcpy, and memset
 runtime-paths.ss: Cooperates with mzc --exe
Inside MzScheme:
 Use SCHEME_INPUT_PORTP() instead of SCHEME_INPORTP()
     SCHEME_OUTPUT_PORTP() instead of SCHEME_OUTPORTP()
     scheme_input_port_record() instead of cast to Scheme_Input_Port*
     scheme_output_port_record() instead of cast to Scheme_Output_Port*
 Added scheme_set_type_equality() with help from Dimitris Vyzovitis
 Added XFORM_START_SKIP, etc.

Version 360, November 2006
Continuations:
 Added delimited continuations: call-with-continuation-prompt,
  call-with-composable-continuation, etc.
 Changed call-with-escape-continuation so that its argument is
  no longer applied in tail position (reverses a change in v350)
Regexps:
 Added case-insensitive mode, multi-line mode, lookahead, lookbehind, 
  non-backtracking, and conditionals to regexp language
 Added pregexp, byte-pregexp, and #px..., which includes numeric
  quantifiers, backreferences char classes, and Unicode predicates
 Added regexp-match?, pregexp?, and byte-pregexp?
 Improved [p]regexp performance
Filesystem:
 Unix and Mac OS X: Changed path operations to use "./~..." as an
  encoding for a relative path "~..."
 Changed simplify-path to always normalize path separators,
  preserve syntactic directoryness, and remove \\?\ from
  Windows paths when possible
 Added path-element->bytes and bytes->path-element
 Changed make-file-or-es active                                                 Version 4.2.1, July 2009
Added string->unreadable-symbol and symbol-interned?
Added syntax-local-lift-provide
Added syntax-local-lift-values-expression
Added identifier-prune-lexical-context and quote-syntax/prune

Version 4.2, May 2009
Changed visiting of modules at phase N to happen only when compilation
 at phase N starts
Changed expander to detect a reaname transformer and install a
 free-identifier=? syntax-object equivalence
Changed provide to convert an exported rename transformer to its
 free-identifier=? target
Added 'not-free-identifier=? syntax property to disable free-identifier=? 
 propagation through a rename transformer
Added prop:rename-transformer and prop:set!-transformer
Fixed scheme/local so that local syntax bindings are visible to later
 local definitions
Changed current-process-milliseconds to accept a thread argument
Added hash-hash-key?, hash-ref!
Added in-sequences, in-cycle

Version 4.1.5, March 2009
Allow infix notation for prefab structure literals
Change quasiquote so that unquote works in value positions of #hash
Change read-syntax to represent #hash value forms as syntax
Added bitwise-bit-field

Version 4.1.4, January 2009
Changed memory accounting to bias charges to parent instead of children
Changed function contracts to preserve tail recursion in many cases
Added scheme/package, scheme/splicing, ffi/objc
Added exception-backtrace support for x86_84+JIT
Added equal?/recur
Added equal<%> and interface* to scheme/class
Added procedure-rename
Added extra arguments to call-with-continuation-prompt
Added extra argument to raise-syntax-error
Added compile-context-preservation-enabled
Added syntax-local-lift-require
Added internal-definition-context-seal, which must be used on an
 internal-definition context before it's part of a fully expanded form
Added syntax-local-make-delta-introducer
Changed make-rename-transformer to accept an introducer argument that
 cooperates with syntax-local-make-delta-introducer
Added internal-defininition-context?
Added identifier-remove-from-defininition-context

Version 4.1.3, November 2008
Changed scheme to re-export scheme/port
In scheme/port: added 
Added call-with-immediate-continuation-mark
In scheme/port: added port->string, port->bytes, port->lines
 port->bytes-lines, display-lines, [call-]with-input-from-{string,bytes},
 and [call-]with-output-to-{string,bytes}
In scheme/file: added file->string, file->bytes, file->lines,
 file->value, file->bytes-lines, write-to-file, display-to-file,
 and display-lines-to-file
Added variable-reference? and empty #%variable-reference form
Extended continuation-marks to work on a thread argument

Version 4.1.2, October 2008
Changed binding of identifiers introduced by unit signatures
 to take into account the signature use's context
Added make-syntax-delta-introducer
Changed continuation-marks to accept a thread argument
Added eqv-based hash tables
Added hash-update and hash-update!
Changed -X and -S to complete directory relative to pwd, and
 changed -S to add after main collects

Version 4.1.1, October 2008
Added read-language
Added module-compiled-language-info, module->language-info,
 and 'module-language property support

Version 4.1, August 2008
Changed namespaces to have a base phase; for example, calling
 eval at compile-time uses a phase-1 namespace
Added logging facilities: make-logger, etc.
Added "inheritance" to structure type properties, and change
 prop:procedure from scheme/base to better support keywords
Added bitwise-bit-set?
Added in-value

Version 4.0, June 2008
>> See MzScheme_4.txt

Version 372, December 2007
Added syntax-local-lift-context
Added #lang
Added require-for-label, provide-for-syntax, provide-for-label,
 identifier-label-binding, module-label-identifier=?

Version 371, August 2007
Added hash-table-iterate-{first,next,key,value}
Added keyword<?
Added make-derived-parameter
Added make-sibling-inspector
Added graph? argument to read[-syntax]/recursive
Added read-accept-infix-dot
Changed #!<space> and #!/ to general comment forms
Added continuation?
Added continuation-prompt-tag?
Inside MzScheme: GC_{malloc,free}_immobile_box
foreign.ss: added {malloc,free}-immobile-box

Version 370, May 2007
Memory management:
 Default build uses 3m instead of CGC
 Added custodian boxes and custodian-memory-accounting-available?
 Added initial custodian argument to custodian-require-memory
Exceptions:
 Removed current-exception-handler and initial-exception-handler
 Added uncaught-exception-handler
 Default error escape handler aborts to default continuation
  tag with the void procedure
 Added call-with-exception-handler
 Changed read-eval-print-loop and the default load handler to wrap
  each evaluation with a prompt and with #%top-interaction
 Changed top-level begin to insert a prompt around each sub-expression
  except the last
 Added #%top-interaction and #%expression
 Changed make-exn to automatically convert a mutable message string
  to an immutable string
Units:
 New unit system provided by MzLib's "unit.ss"
Ports and pathnames:
 Added prop:input-port and prop:output-port
 Added support for manipulating filesystem paths that work on 
  other platforms
 Added string->path-element and path-element->string
 Changed path->directory-path, simplify-path, and split-path to include
  a trailing path separator even when the result would be a directory
  path without it
 Changed simplify-path for Windows paths to replace / with \
 Changed current-directory to apply path->directory-path to given paths
 Added reset?, start-, and end-index arguments to get-output-bytes
 Added port-closed?
 Added optional argument to tcp-addresses to get port numbers
Syntax and loading:
 Default load handler enables #reader (even when not reading a module)
 Added module-path-index-resolve
 Added syntax-local-expand-expression
 Changed dyanmic-require to expand requests for exported syntax
  bindings
 Added an argument to syntax-local-certifier indicating whether the
  generated procedure attaches active or inactive certificates
 Changed macro expansion of bound identifiers so that `local-expand'
  works with an empty stop list
 Module top-level enforces initial categorization of expressions
  versus other forms
 Changed H-expression parsing to represent angle brackets specially
Misc:
 Changed print-struct default to #t instead of #f
 Added parameterize*
 Added 'gc and 'so-suffix flags for system-type
 Added vector->values
 Changed char-whitespace? to produce #t for #\u0085
 Added -p, -P, and -Q command-line options
 Added procedure-struct-type?
 Added system-idle-evt
 Fixed mzc --exe to work with C-implemented extension modules
MzLib:
 serialize.ss: Path includes the path's convention
 foreign.ss: Added ptr-add, memmove, memcpy, and memset
 runtime-paths.ss: Cooperates with mzc --exe
Inside MzScheme:
 Use SCHEME_INPUT_PORTP() instead of SCHEME_INPORTP()
     SCHEME_OUTPUT_PORTP() instead of SCHEME_OUTPORTP()
     scheme_input_port_record() instead of cast to Scheme_Input_Port*
     scheme_output_port_record() instead of cast to Scheme_Output_Port*
 Added scheme_set_type_equality() with help from Dimitris Vyzovitis
 Added XFORM_START_SKIP, etc.

Version 360, November 2006
Continuations:
 Added delimited continuations: call-with-continuation-prompt,
  call-with-composable-continuation, etc.
 Changed call-with-escape-continuation so that its argument is
  no longer applied in tail position (reverses a change in v350)
Regexps:
 Added case-insensitive mode, multi-line mode, lookahead, lookbehind, 
  non-backtracking, and conditionals to regexp language
 Added pregexp, byte-pregexp, and #px..., which includes numeric
  quantifiers, backreferences char classes, and Unicode predicates
 Added regexp-match?, pregexp?, and byte-pregexp?
 Improved [p]regexp performance
Filesystem:
 Unix and Mac OS X: Changed path operations to use "./~..." as an
  encoding for a relative path "~..."
 Changed simplify-path to always normalize path separators,
  preserve syntactic directoryness, and remove \\?\ from
  Windows paths when possible
 Added path-element->bytes and bytes->path-element
 Changed make-file-or-es active                                                 Version 4.2.1, July 2009
Added string->unreadable-symbol and symbol-interned?
Added syntax-local-lift-provide
Added syntax-local-lift-values-expression
Added identifier-prune-lexical-context and quote-syntax/prune

Version 4.2, May 2009
Changed visiting of modules at phase N to happen only when compilation
 at phase N starts
Changed expander to detect a reaname transformer and install a
 free-identifier=? syntax-object equivalence
Changed provide to convert an exported rename transformer to its
 free-identifier=? target
Added 'not-free-identifier=? syntax property to disable free-identifier=? 
 propagation through a rename transformer
Added prop:rename-transformer and prop:set!-transformer
Fixed scheme/local so that local syntax bindings are visible to later
 local definitions
Changed current-process-milliseconds to accept a thread argument
Added hash-hash-key?, hash-ref!
Added in-sequences, in-cycle

Version 4.1.5, March 2009
Allow infix notation for prefab structure literals
Change quasiquote so that unquote works in value positions of #hash
Change read-syntax to represent #hash value forms as syntax
Added bitwise-bit-field

Version 4.1.4, January 2009
Changed memory accounting to bias charges to parent instead of children
Changed function contracts to preserve tail recursion in many cases
Added scheme/package, scheme/splicing, ffi/objc
Added exception-backtrace support for x86_84+JIT
Added equal?/recur
Added equal<%> and interface* to scheme/class
Added procedure-rename
Added extra arguments to call-with-continuation-prompt
Added extra argument to raise-syntax-error
Added compile-context-preservation-enabled
Added syntax-local-lift-require
Added internal-definition-context-seal, which must be used on an
 internal-definition context before it's part of a fully expanded form
Added syntax-local-make-delta-introducer
Changed make-rename-transformer to accept an introducer argument that
 cooperates with syntax-local-make-delta-introducer
Added internal-defininition-context?
Added identifier-remove-from-defininition-context

Version 4.1.3, November 2008
Changed scheme to re-export scheme/port
In scheme/port: added 
Added call-with-immediate-continuation-mark
In scheme/port: added port->string, port->bytes, port->lines
 port->bytes-lines, display-lines, [call-]with-input-from-{string,bytes},
 and [call-]with-output-to-{string,bytes}
In scheme/file: added file->string, file->bytes, file->lines,
 file->value, file->bytes-lines, write-to-file, display-to-file,
 and display-lines-to-file
Added variable-reference? and empty #%variable-reference form
Extended continuation-marks to work on a thread argument

Version 4.1.2, October 2008
Changed binding of identifiers introduced by unit signatures
 to take into account the signature use's context
Added make-syntax-delta-introducer
Changed continuation-marks to accept a thread argument
Added eqv-based hash tables
Added hash-update and hash-update!
Changed -X and -S to complete directory relative to pwd, and
 changed -S to add after main collects

Version 4.1.1, October 2008
Added read-language
Added module-compiled-language-info, module->language-info,
 and 'module-language property support

Version 4.1, August 2008
Changed namespaces to have a base phase; for example, calling
 eval at compile-time uses a phase-1 namespace
Added logging facilities: make-logger, etc.
Added "inheritance" to structure type properties, and change
 prop:procedure from scheme/base to better support keywords
Added bitwise-bit-set?
Added in-value

Version 4.0, June 2008
>> See MzScheme_4.txt

Version 372, December 2007
Added syntax-local-lift-context
Added #lang
Added require-for-label, provide-for-syntax, provide-for-label,
 identifier-label-binding, module-label-identifier=?

Version 371, August 2007
Added hash-table-iterate-{first,next,key,value}
Added keyword<?
Added make-derived-parameter
Added make-sibling-inspector
Added graph? argument to read[-syntax]/recursive
Added read-accept-infix-dot
Changed #!<space> and #!/ to general comment forms
Added continuation?
Added continuation-prompt-tag?
Inside MzScheme: GC_{malloc,free}_immobile_box
foreign.ss: added {malloc,free}-immobile-box

Version 370, May 2007
Memory management:
 Default build uses 3m instead of CGC
 Added custodian boxes and custodian-memory-accounting-available?
 Added initial custodian argument to custodian-require-memory
Exceptions:
 Removed current-exception-handler and initial-exception-handler
 Added uncaught-exception-handler
 Default error escape handler aborts to default continuation
  tag with the void procedure
 Added call-with-exception-handler
 Changed read-eval-print-loop and the default load handler to wrap
  each evaluation with a prompt and with #%top-interaction
 Changed top-level begin to insert a prompt around each sub-expression
  except the last
 Added #%top-interaction and #%expression
 Changed make