WinZigC programming language

This tree includes the code for a compiler for the language specified by WinZigC language spectification. It generates LLVM bitcode for the WinZigC program and compiles the bitcode to an executable binary using the Clang backend.

Related content

Blog posts

• The journey of implementing the WinZigC programming language
• Making WinZigC programs debuggable

Videos

• Demo: Debugging a WinZigC program using LLDB

Give me some example programs!

You can find a set of example programs in example-programs and optimized and non optimized control flow graphs for the corresponding programs in cfg.

How to run/debug a WinZigC program?

Visit developer guide.

Memory allocation

We stay in stack memory (within functions) and global static memory (program-global memory) until the program exits. Therefore, there is no heap memory allocation or access.

Global variables

You can declare variables in the global scope that can be modified from anywhere in your program. Global variables are cleaned up when your program exits.

Local variables

Memory is allocated for variables declared within a function (parameters and local variable declarations). All local variable memory allocations are cleaned up when the function exits.

Features

Built-in types

• integer - 32 bit.

  If your input or the program processes intermediate values that do not fit into 32 bits, unexpected results may occur.

• char - 8 bit ASCII characters.

  No Unicode characters.

• boolean - Think of it as 1 bit. You can assign true and false values.

User types

Users can define enumetated types:

type Result = ( Composite, Prime, TooBig );

Functions

Users can define functions and call them. For example:

Define a function:

function Factor ( i : integer ):integer;
var
    j : integer;
begin
    if i > 0 then
	for (j := 1; j <= i; j:=j+1)
	    if i mod j = 0 then output ( j )
end Factor;

Call the function:

d := Factor(120);

Discarding output of a function

To discard a function output by assigning it to a discard variable d:

d := MyPrintFunc(12, 'c', true);

Return value of a function

WinZigC supports two ways to change the return value:

• Assign a value to the function name:

  FuncName := 7;
  

  This will not cause the function to exit.

• Using a return statement:

  return 7;
  

  This will cause the function to exit.

Buit-in functions

• read - Read user input from the command line.

  Note: [Enter] key press is considered as input when reading to a char.

• output - Write output to the command line.

Commeting code

• Single-line comment:

# Please ingore this line of text

• Multi-line/block comments:

{ Zero line of comment
    First line of the comment
    Second line of the comment
ingore this as well }

Control flows

Branching

• if-else two-way branching

  if n > 0 then
      return (n + fact(sum(n-1)))
  else return (0)
  

• case multi-way branching

  case R of
      Composite:  output ('C');
      Prime:      output ('P');
      TooBig:     output ('B');
  end
  

Looping

• for looping

  for (i:=1; i<=7; i:=i+1)
  begin
      output (fibonacci(i))
  end
  

• while looping

  while ((c = '+') or (c = '-')) do begin
      if (c = '+') then begin
          d:=GetNext(3);
          v := v + T(3);
      end
      else begin { c = '-' }
          d:=GetNext(3);
          v := v - T(3)
      end;
  end;
  

• repeat-until looping

  repeat
      read(i);
      d:=Factor(i)
  until i <= 0
  

Operators

Assignment

• := - Assignment
• :=: - Swap assignment

Binary

• * - Multiplication
• / - Division
• mod - Modulus
• + - Addition
• - - Subtraction
• < - Less than
• <= - Less than or equal to
• > - Greater than
• >= - Greater than or equal to
• = - Equal to
• <> - Not equal to
• and - Logical and
• or - Logical or

Unary

• not - Logical not
• - - Negative
• + - Positive
• succ(..) - Successive value (++ operator semantics as in other languages)
• pred(..) - Predecessor value (-- operator semantics as in other languages)