yabasic.1

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   the file. This is simply done by putting a hash ('#') followed by the number
   of the file after the keyword input (for reading from) or print (for writing
   to a file) respectively.

   If you need more control, you may consider reading and writing one byte at a
   time, using the multi-purpose commands peek and poke.

Subroutines and Libraries

   The best way to break any yabasic-program into smaller, more manageable
   chunks are subroutines and libraries. They are yabasic's most advanced means
   of structuring a program.

   Subroutines are created with the command sub. they accept parameters and may
   return a value. Subroutines can be called much like any builtin function of
   yabasic; therefore they allow to extend the language itself.

   Once you have created a set of related subroutines and you feel that they
   could be useful in other programs too, you may collect them into a library.
   Such a library is contained within a separate file and may be included in
   any of your programs, using the keyword import.

String processing

   yabasic has the usual functions to extract parts from a string: left$, mid$
   and right$. Note, that all of them can be assigned to, i.e. they may change
   part of a string.

   If you want to split a string into tokens you should use the functions token
   or split.

   There is quite a bunch of other string-processing functions like upper$
   (converting to upper case), instr (finding one string within the other),
   chr$ (converting an ascii-code into a character), glob (testing a string
   against a pattern) and more. Just follow the links.

Arithmetic

   Yabasic handles numbers and arithmetic: You may calculate trigonometric
   functions like sin or atan, or logarithms (with log). Bitwise operations,
   like and or or are available as well min or max (calculate the minimum or
   maximum of its argument) or mod or int (reminder of a division or integer
   part or a number).

Data and such

   You may store data within your program within data-statements; during
   execution you will probably want to read it into arrays, which must have
   been dimed before.

Other interesting commands.

     * Yabasic programs may start other programs with the commands system and
       system$.
     * peek and poke allow to get and set internal information; either for the
       operating system (i.e. Unix or Windows) or yabasic itself.
     * The current time or date can be retrieved with (guess what !) time$ and
       date$.

Chapter 5. All commands and functions of yabasic listed by topic

   Number processing and conversion
   Conditions and control structures
   Data keeping and processing
   String processing
   File operations and printing
   Subroutines and libraries
   Other commands
   Graphics and printing

Number processing and conversion

   abs()
          returns the absolute value of its numeric argument

   acos()
          returns the arcus cosine of its numeric argument

   and()
          the bitwise arithmetic and

   asin()
          returns the arcus sine of its numeric argument

   atan()
          returns the arctangent of its numeric argument

   bin$()
          converts a number into a sequence of binary digits

   cos()
          return the cosine of its single argument

   dec()
          convert a base 2 or base 16 number into decimal form

   eor()
          compute the bitwise exclusive or of its two arguments

   euler
          another name for the constant 2.71828182864

   exp()
          compute the exponential function of its single argument

   frac()
          return the fractional part of its numeric argument

   int()
          return the integer part of its single numeric argument

   log()
          compute the natural logarithm

   max()
          return the larger of its two arguments

   min()
          return the smaller of its two arguments

   mod()
          compute the remainder of a division

   or()
          arithmetic or, used for bit-operations

   pi
          a constant with the value 3.14159

   ran()
          return a random number

   sig()
          return the sign of its argument

   sin()
          return the sine of its single argument

   sqr()
          compute the square of its argument

   sqrt()
          compute the square root of its argument

   tan()
          return the tangent of its argument

   xor()
          compute the exclusive or

   ** or ^
          raise its first argument to the power of its second

Conditions and control structures

   and
          logical and, used in conditions

   break
          breaks out of a switch statement or a loop

   case
          mark the different cases within a switch-statement

   continue
          start the next iteration of a for-, do-, repeat- or while-loop

   default
          mark the default-branch within a switch-statement

   do
          start a (conditionless) do-loop

   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

   false
          a constant with the value of 0

   fi
          another name for endif

   for
          starts a for-loop

   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)

   if
          evaluate a condition and execute statements or not, depending on the
          result

   label
          mark a specific location within your program for goto, gosub or
          restore

   loop
          marks the end of an infinite loop

   next
          mark the end of a for loop

   not
          negate an expression; can be written as !

   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

   logical or
          logical or, used in conditions

   pause
          pause, sleep, wait for the specified number of seconds

   repeat
          start a repeat-loop

   return
          return from a subroutine or a gosub

   sleep
          pause, sleep, wait for the specified number of seconds

   switch
          select one of many alternatives depending on a value

   then
          tell the long from the short form of the if-statement

   true
          a constant with the value of 1

   until
          end a repeat-loop

   wait
          pause, sleep, wait for the specified number of seconds

   wend
          end a while-loop

   while
          start a while-loop

   :
          separate commands from each other

Data keeping and processing

   arraydim()
          returns the dimension of the array, which is passed as an array
          reference

   arraysize()
          returns the size of a dimension of an array

   data
          introduces a list of data-items

   dim
          create an array prior to its first use

   read
          read data from data-statements

   redim
          create an array prior to its first use. A synonym for dim

   restore
          reposition the data-pointer

String processing

   asc()
          accepts a string and returns the position of its first character
          within the ascii charset

   chr$()
          accepts a number and returns the character at this position within
          the ascii charset

   glob()
          check if a string matches a simple pattern

   hex$()
          convert a number into hexadecimal

   instr()
          searches its second argument within the first; returns its position
          if found

   left$()
          return (or change) left end of a string

   len()
          return the length of a string

   lower$()
          convert a string to lower case

   ltrim$()
          trim spaces at the left end of a string

   mid$()
          return (or change) characters from within a string

   right$()
          return (or change) the right end of a string

   split()
          split a string into many strings

   str$()
          convert a number into a string

   token()
          split a string into multiple strings

   trim$()
          remove leading and trailing spaces from its argument

   upper$()
          convert a string to upper case

   val()
          converts a string to a number

File operations and printing

   at()
          can be used in the print-command to place the output at a specified
          position

   beep
          ring the bell within your computer; a synonym for bell

   bell
          ring the bell within your computer (just as beep)

   clear screen
          erases the text window

   close
          close a file, which has been opened before

   close printer
          stops printing of graphics

   print color
          print with color

   print colour
          see print color

   eof
          check, if an open file contains data

   getscreen$()
          returns a string representing a rectangular section of the text
          terminal

   inkey$
          wait, until a key is pressed

   input
          read input from the user (or from a file) and assign it to a variable

   line input
          read in a whole line of text and assign it to a variable

   open
          open a file

   open printer
          open printer for printing graphics

   print
          Write to terminal or file

   putscreen
          draw a rectangle of characters into the text terminal

   reverse
          print reverse (background and foreground colors exchanged)

   screen
          as clear screen clears the text window

   seek()
          change the position within an open file

   tell
          get the current position within an open file

   using
          Specify the format for printing a number

   #
          either a comment or a marker for a file-number

   @
          synonymous to at

   ;
          suppress the implicit newline after a print-statement

Subroutines and libraries

   end sub
          ends a subroutine definition

   export
          mark a function as globally visible

   import
          import a library

   local
          mark a variable as local to a subroutine

   numparams
          return the number of parameters, that have been passed to a
          subroutine

   return
          return from a subroutine or a gosub

   static
          preserves the value of a variable between calls to a subroutine

   step
          specifies the increment step in a for-loop

   sub
          declare a user defined subroutine

Other commands

   bind()
          Binds a yabasic-program and the yabasic-interpreter together into a
          standalone program.

   compile
          compile a string with yabasic-code on the fly

   date$
          returns a string with various components of the current date

   doc
          special comment, which might be retrieved by the program itself

   docu$
          special array, containing the contents of all docu-statement within
          the program

   error
          raise an error and terminate your program

   execute$()
          execute a user defined subroutine, which must return a string