Yabasic

Table of Contents

1. Introduction
- About this document
- About yabasic
2. The yabasic-program under Windows
3. The yabasic-program under Unix
4. Command line options of yabasic
5. All commands and functions of yabasic listed by topic
6. Some features and general concepts of yabasic
7. All commands and functions of yabasic grouped alphabetically
- A
  - abs() — returns the absolute value of its numeric argument
  - acos() — returns the arcus cosine of its numeric argument
  - and — logical and, used in conditions
  - and() — the bitwise arithmetic and
  - arraydim() — returns the dimension of the array, which is passed as an array reference
  - arraysize() — returns the size of a dimension of an array
  - asc() — accepts a string and returns the position of its first character within the ascii charset
  - asin() — returns the arcus sine of its numeric argument
  - at() — can be used in the commands print and input to place the output at a specified position
  - atan() — returns the arctangent of its numeric argument
- B
  - backcolor — change color for background of graphic window
  - beep — ring the bell within your computer; a synonym for bell
  - bell — ring the bell within your computer (just as beep)
  - bin$() — converts a number into a sequence of binary digits
  - bind() — binds a yabasic-program and the yabasic-interpreter together into a standalone program
  - bitnot() — the bitwise arithmetic not
  - box — draw a rectangle. A synonym for rectangle
  - break — breaks out of one or more loops or switch statements
- C
  - case — mark the different cases within a switch-statement
  - ceil() — compute the ceiling for its (float) argument
  - chomp$() — remove a single trailing newline from its string-argument; if the string does not end in a newline, the string is returned unchanged
  - chr$() — accepts a number and returns the character at this position within the ascii charset
  - circle — draws a circle in the graphic-window
  - clear — erase circles, rectangles or triangles
  - clear screen — erases the text window
  - clear window — clear the graphic window and begin a new page, if printing is under way
  - close — close a file, which has been opened before
  - close curve — close a curve, that has been drawn by the line-command
  - close printer — stops printing of graphics
  - close window — close the graphics-window
  - color — change color for any subsequent drawing-command
  - compile — compile a string with yabasic-code on the fly
  - continue — start the next iteration of a for-, do-, repeat- or while-loop
  - cos() — return the cosine of its single argument
- D
  - data — introduces a list of data-items
  - date$ — returns a string with various components of the current date
  - dec() — convert a base 2 or base 16 number into decimal form
  - default — mark the default-branch within a switch-statement
  - dim — create an array prior to its first use
  - do — start a (conditionless) do-loop
  - doc — special comment, which might be retrieved by the program itself
  - docu$ — special array, containing the contents of all docu-statement within the program
  - dot — draw a dot in the graphic-window
- E
  - else — mark an alternative within an if-statement
  - elsif — starts an alternate condition within an if-statement
  - end — terminate your program
  - endif — ends an if-statement
  - end sub — ends a subroutine definition
  - eof — check, if an open file contains data
  - eor() — compute the bitwise exclusive or of its two arguments
  - error — raise an error and terminate your program
  - euler — another name for the constant 2.71828182864
  - eval() — compile and execute a single numeric expression
  - eval$() — compile and execute a single string-expression
  - execute() — execute a user defined subroutine, which must return a number
  - execute$() — execute a user defined subroutine, which must return a string
  - exit — terminate your program
  - exp() — compute the exponential function of its single argument
  - export — mark a function as globally visible
- F
  - false — a constant with the value of 0
  - fi — another name for endif
  - fill — draw a filled circles, rectangles or triangles
  - floor() — compute the floor for its (float) argument
  - for — starts a for-loop
  - foreign_buffer_alloc$() — Create a new buffer for use in a foreign function call
  - foreign_buffer_dump$() — return the content of a buffer as a hex-encoded string
  - foreign_buffer_free — free a foreign buffer
  - foreign_buffer_get() — extract a number from a foreign buffer
  - foreign_buffer_get$() — extract a string from a foreign buffer
  - foreign_buffer_get_buffer$() — take a buffer and construct a handle to a second buffer from its content
  - foreign_buffer_set — store a given value within a buffer
  - foreign_buffer_set_buffer — store a pointer to one buffer within another buffer
  - foreign_buffer_size() — return the size of the foreign buffer
  - foreign_function_call() — call a function (returning a number) from a non-yabasic library or dll
  - foreign_function_call$() — call a function (returning a string or a buffer) from a non-yabasic library or dll
  - foreign_function_size() — return the size of one of the types available for foreign function calls
  - frnbf_ and frnfn_ — Abbreviations for foreign_buffer_ and foreign_function_
  - frac() — return the fractional part of its numeric argument
- G
  - getbit$() — return a string representing the bit pattern of a rectangle within the graphic window
  - getscreen$() — returns a string representing a rectangular section of the text terminal
  - glob() — check if a string matches a simple pattern
  - gosub — continue execution at another point within your program (and return later)
  - goto — continue execution at another point within your program (and never come back)
- H
  - hex$() — convert a number into hexadecimal
- I
  - if — evaluate a condition and execute statements or not, depending on the result
  - import — import a library
  - inkey$ — wait, until a key is pressed
  - input — read input from user or file and assign it to a variable
  - instr() — searches its second argument within the first; returns its position if found
  - int() — return the integer part of its single numeric argument
- L
  - label — mark a specific location within your program for goto, gosub or restore
  - left$() — return (or change) left end of a string
  - len() — return the length of a string
  - line — draw a line
  - line input — read in a whole line of text and assign it to a variable
  - local — mark a variable as local to a subroutine
  - log() — compute the natural logarithm
  - loop — marks the end of an infinite loop
  - lower$() — convert a string to lower case
  - ltrim$() — trim spaces at the left end of a string
- M
  - max() — return the larger of its two arguments
  - mid$() — return (or change) characters from within a string
  - min() — return the smaller of its two arguments
  - mod — compute the remainder of a division
  - mouseb — extract the state of the mousebuttons from a string returned by inkey$
  - mousemod — return the state of the modifier keys during a mouseclick
  - mousex — return the x-position of a mouseclick
  - mousey — return the y-position of a mouseclick
- N
  - new curve — start a new curve, that will be drawn with the line-command
  - next — mark the end of a for loop
  - not — negate a logical expression; can be written as !
  - numparams — return the number of parameters, that have been passed to a subroutine
- O
  - on gosub — jump to one of multiple gosub-targets
  - on goto — jump to one of many goto-targets
  - on interrupt — change reaction on keyboard interrupts
  - open — open a file
  - open printer — open printer for printing graphics
  - open window — open a graphic window
  - logical or — logical or, used in conditions
  - or() — arithmetic or, used for bit-operations
- P
  - pause — pause, sleep, wait for the specified number of seconds
  - peek — retrieve various internal informations (numeric)
  - peek$ — retrieve various internal informations (strings)
  - pi — a constant with the value 3.14159
  - poke — change selected internals of yabasic
  - print — Write to terminal or file
  - print or input with color — print or input-prompt with color
  - print colour — see print color
  - putbit — draw a rectangle of pixels encoded within a string into the graphics window
  - putscreen — draw a rectangle of characters into the text terminal
- R
  - ran() — return a random number
  - read — read data from data-statements
  - rectangle — draw a rectangle
  - redim — create an array prior to its first use. A synonym for dim
  - rem — start a comment
  - repeat — start a repeat-loop
  - restore — reposition the data-pointer
  - return — return from a subroutine or a gosub
  - reverse — print reverse (background and foreground colors exchanged)
  - right$() — return (or change) the right end of a string
  - rinstr() — find the rightmost occurrence of one string within the other
  - round() — round its argument to the nearest integer
  - rtrim$() — trim spaces at the right end of a string
- S
  - screen — as clear screen clears the text window
  - seek() — change the position within an open file
  - sig() — return the sign of its argument
  - sin() — return the sine of its single argument
  - shl() — shift its argument bitwise to the left
  - shr() — shift its argument bitwise to the right
  - sleep — pause, sleep, wait for the specified number of seconds
  - split() — split a string into many strings
  - sqr() — compute the square of its argument
  - sqrt() — compute the square root of its argument
  - static — preserves the value of a variable between calls to a subroutine
  - step — specifies the increment step in a for-loop
  - str$() — convert a number into a string
  - string$() — create a new string by repeating the given one a certain number of times
  - sub — declare a user defined subroutine
  - switch — select one of many alternatives depending on a value
  - system() — hand the name of an external command over to your operating system and return its exitcode
  - system$() — hand the name of an external command over to your operating system and return its output
- T
  - tan() — return the tangent of its argument
  - tell — get the current position within an open file
  - text — write text into your graphic-window
  - then — tell the long from the short form of the if-statement
  - time$ — return a string containing the current time
  - to — this keyword appears as part of other statements
  - token() — split a string into multiple strings
  - triangle — draw a triangle
  - trim$() — remove leading and trailing spaces from its argument
  - true — a constant with the value of 1
- U
  - until — end a repeat-loop
  - upper$() — convert a string to upper case
  - using — Specify the format for printing a number
- V
  - val() — converts a string to a number
- W
  - wait — pause, sleep, wait for the specified number of seconds
  - wend — end a while-loop
  - while — start a while-loop
  - window origin — move the origin of a window
- X
  - xor() — compute the exclusive or
- Symbols and Special characters
  - # — either a comment or a marker for a file-number
  - // — starts a comment
  - @ — synonymous to at
  - : — separate commands from each other
  - ; — suppress the implicit newline after a print-statement
  - ** or ^ — raise its first argument to the power of its second
  - < <= > >= = == <> != — Compare numbers or strings
8. A few example programs
9. The Copyright of yabasic

Chapter 1. Introduction

About this document
About yabasic

About this document

This document describes yabasic. You will find information about the yabasic interpreter (the program yabasic under Unix or yabasic.exe under Windows) as well as the language (which is, of course, a sort of basic) itself.

This document applies to version 2.91 of yabasic

However, it does not contain the latest news about yabasic or a FAQ. As such information tends to change rapidly, it is presented online only at www.yabasic.de.

Although basic has its reputation as a language for beginning programmers, this is not an introduction to programming at large. Rather this text assumes, that the reader has some (moderate) experience with writing and starting computer programs.

About yabasic

yabasic is a traditional basic interpreter. It understands most of the typical basic-constructs, like goto, gosub, line numbers, read, data or string-variables with a trailing '$'. But on the other hand, yabasic implements some more advanced programming-constructs like subroutines or libraries (but not objects). yabasic works much the same under Unix and Windows.

yabasic puts emphasis on giving results quickly and easily; therefore simple commands are provided to open a graphic window, print the graphics or control the console screen and get keyboard or mouse information. The example below opens a window, draws a circle and prints the graphic:

open window 100,100
open printer
circle 50,50,40
text 10,50,"Press any key to get a printout"
clear screen
inkey$
close printer
close window

This example has fewer lines, than it would have in many other programming languages. In the end however yabasic lacks behind more advanced and modern programming languages like C++ or Java. But as far as it goes it tends to give you results more quickly and easily.

Chapter 2. The yabasic-program under Windows

Starting yabasic
Options
The context Menu

Starting yabasic

Once, yabasic has been set up correctly, there are three ways to start it:

Right click on your desktop: The desktop menu appears with a submenu named new. From this submenu choose yabasic. This will create a new icon on your desktop. If you right click on this icon, its context menu will appear; choose Execute to execute the program.
As a variant of the way described above, you may simply create a file with the ending .yab (e.g. with your favorite editor). Everything else then works as described above.
From the start-menu: Choose yabasic from your start-menu. A console-window will open and you will be asked to type in your program. Once you are finished, you need to type return twice, and yabasic will parse and execute your program.

Note

This is not the preferred way of starting yabasic ! Simply because the program, that you have typed, can not be saved and will be lost inevitably ! There is no such thing as a save-command and therefore no way to conserve the program, that you have typed. This mode is only intended for quick hacks, and short programs.

Options

Under Windows yabasic will mostly be invoked by double-clicking on an appropriate icon; this way you do not have a chance to specify any of the command line options below. However, advanced users may change the librarypath in the registry, which has the same effect as specifying it as an option on the