WIS

WIS is a concatenative, stack-based programming language inspired by Forth.

Quick Start

Running mode is deprecated now. So only compilation mode is currently available.

Compilation

$ cat ./goo.wis
use "std.wis"
"Hello, world!\n" puts

$ ./wis -quiet -r ./goo.wis
Hello, world!

Language

Basic operations

<int>

Pushes an integer number to the stack

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<string>

Pushes size of string represented as int value, and ptr where string starts at

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put

Removes and prints unsigned integer from top of the stack

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fputs

Built-in shortcut for sequence of operations: sys_write syscall3 drop. The o reason why it is a built-in operation and not a standard binding, to save type checking for this puts operations. Because we can't correctly check types of syscalls' arguments

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Basic stack manipulations

copy

Duplicates a value on top of the stack

Stack: 1 2 => 1 2 2

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over

Duplicates previous value from stack to top

Stack: 1 2 => 1 2 1

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swap

Swaps around 2 top values in the stack

Stack: 1 2 => 2 1

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drop

Removes top value from the stack

Stack: 1 2 => 1

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rot

Rotate top 3 values on the stack to right direction

Stack: 1 2 3 => 3 1 2

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2swap

Swaps 2 pairs of arguments on top of the stack

Stack: 1 2 3 4 => 3 4 1 2

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Memory manipulation

• mem operation pushes to the stack a pointer to memory buffer, where you can read and write some data
• @8 and @64 (forth-like load) operations loads a byte or 64-bit value from provided pointer and pushes this value to the stack
• !8 and !64 (forth-like store) operations puts a byte or 64-bit value to the memory buffer

See examples here and here

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Bindings

bind keyword provide an ability to create some sort of inline procedures (VERY WEIRD, OFC), but al least that is something.

At the compilation step, name of binding will expand to operations, bind to that name

Example:

bind print-sum + put end

34 35 print-sum

Actually, that program after compilation will turn to that view:

34 35 + put

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Control flows

if statement

Usage:

34 35 + 69 == if
  1 put
else
  0 put
end

if statement currently have no elif, but uou can combine block like below:

false if
  1 put
else true if 
  2 put
else
  3 put
end end

But it always will end with this weird end-trail

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while loop

Usage:

1 while copy 10 <= do
  copy put
end drop

This program will print numbers from 0 to 10

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Other

use keyword provide an ability to include outer file to current. If you have ANY operations outside the bindings in the including file, they will NOT ingore by the compiler.

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syscal<n> allows you to manipulate directly with linux kernel.

Example:

syscall3 accepts 3 arguments and 1 additional argument for syscall number

"Some data\n" 1 1 syscall3
69 60 syscall1

That simple program will print "Some data" to stdout and exit with 69 exit code

For now, I have no idea how to create proper type checking for syscalls' arguments, so now we are just checking their amount only

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Standard library

Constants

• stdin, sydout and stderr are constants for default streams

Wrappers

• write, read, open and exit are wrappers for common and used syscalls
• puts wrapper for printing strings to stdout
• eputs wrapper for printing strings to stderr
• putd is a binding for printing signed integers

Stack operations

• 2copy: Stack: 1 2 => 1 2 1 2
• 2drop: Stack: 1 2 3 => 1

String bindgings

• strlen - binding for calculate string's length
• endl just shortcut for "\n" symbol