en:presentation

Différences

Ci-dessous, les différences entre deux révisions de la page.

Lien vers cette vue comparative

Les deux révisions précédentes Révision précédente
Prochaine révision		 Révision précédente
en:presentation [2025/12/24 16:34] – rooten:presentation [2026/04/03 12:13] (Version actuelle) – root
Ligne 1: Ligne 1:
 ===== W Language Description ===== ===== W Language Description =====
-The W language is a procedural, loosely typed language with flexible and powerful data structures.+The W language is a procedural language, with dynamic typing and with flexible and powerful data structures.
 ==== Comments ==== ==== Comments ====
 Comments are written after the semicolon (;). They can appear either alone on a line or at the end of a line after an instruction. Comments are written after the semicolon (;). They can appear either alone on a line or at the end of a line after an instruction.
 Empty lines are considered comments. Empty lines are considered comments.
-<code w>+<code wlang>
 ; First comment ; First comment
      ; Other comment      ; Other comment
Ligne 20: Ligne 20:
 During execution, any exception automatically causes a jump to the beginning of the exception block of the current program or subroutine. This is the equivalent of a systematic ''try/catch'' loop. During execution, any exception automatically causes a jump to the beginning of the exception block of the current program or subroutine. This is the equivalent of a systematic ''try/catch'' loop.
 Let's revisit the classic //Hello world// example : Let's revisit the classic //Hello world// example :
-<code w hello.w>+<code wlang hello.w>
 ; classic example... ; classic example...
  
Ligne 37: Ligne 37:
  
 The source file to be included must be located in the [[w:env|WSRC]] directory. The source file to be included must be located in the [[w:env|WSRC]] directory.
-<code w>+<code wlang>
 include "calcul.w" include "calcul.w"
 </code> </code>
Ligne 48: Ligne 48:
 ==== Data Types ==== ==== Data Types ====
 Variables must be declared, but without a type, and can be declared anywhere in the code. They only become usable after their declaration; otherwise, an exception will be thrown. Variables must be declared, but without a type, and can be declared anywhere in the code. They only become usable after their declaration; otherwise, an exception will be thrown.
-<code w>+<code wlang>
 ; declaration of 3 variables ; declaration of 3 variables
 declare x, y, tmp declare x, y, tmp
Ligne 59: Ligne 59:
   * Subroutine: stores the address of a subroutine   * Subroutine: stores the address of a subroutine
   * Object: identical to Hashtable and allows storing/managing classes and objects   * Object: identical to Hashtable and allows storing/managing classes and objects
-  * +  * Param: Since parameters passed to subroutines are all by reference, each parameter is of this type, pointing to the actual variable: each action on the parameter will actually act on the variable passed as a parameter. 
 + 
 +An 8th type, Buffer, is used only internally by the W executor (for managing the expression and call stack). 
 + 
 +=== Scope === 
 +Variables declared in the main block (begin/background) of the program have global scope. 
 +Variables declared in libraries and subroutines have local scope to the subroutine. 
 +Subroutines, classes, and objects have global scope, even if they appear in a subroutine (**__To be specified__** when created from a //library//). 
 +Variables belonging to a hashtable are only accessible via the hashtable, except for classes and objects stored globally. 
 + 
 +=== Usage === 
 +Variables are assigned using the //let// statement. It is possible to //de-assign// a variable with the //delet// instruction. In this case, the variable is deleted and is no longer declared. Adding variables to a Hashtable does not require declaration, but they are assigned and unassigned like other variables. The syntax to use is ''<varht>.<member>'' 
 +<code wlang> 
 +declare h, n, d 
 + 
 +let h = {} ; h is a Hashtable 
 +let n = -12.34 ; n is a Number 
 +let d = "coucou" ; d is a Dynamic 
 + 
 +; h will contain 2 variables of type Number, x and y, which are not declared with "declare" 
 +let h.x = 10 
 +let h.y = 20 
 + 
 +</code> 
 +==== Exceptions ==== 
 +Every program and subroutine must contain an instruction [[w:instr:except|except]]. When an exception occurs, the executor automatically jumps to the exception block, that is, to the first instruction following the line //except//. Within the processing block, it is possible to force an exception to be thrown with the instruction [[w:instr:throw|throw]]. Within the exception block, by default, if nothing is coded, the exception propagates to the calling program, and thus travels back to the main program. In this case, the exception returns an exit code to the shell corresponding to the exception code (handling the return code using 8 bits). Also within the exception block, it is possible to cancel the current exception with the instruction [[w:instr:catch|catch]]: the program immediately exits the block without an exception. It is also possible to throw another exception with the `//throw//` instruction: the program also immediately exits the block, with the exception code specified in `//throw//`. 
 + 
 +Finally, the system variable `[w:instr:varsys|@except]` contains the current exception, and `[w:instr:varsys|@exceptline]` gives the line number of the source code that caused the exception. 
 +At any time, the `[w:instr:return|return]` instruction allows exiting the current block, either the processing block or the exception block, without changing the exit conditions (exception). When the current block is the main block, `//return//` causes the program to terminate and returns to the caller (the shell, etc.) with the current exception code (8 bits) returned, or 0 if there is no exception. 
 + 
 +Example 
 +<code wlang> 
 +begin test 
 +  declare x 
 +  let x = 10 
 +  let y = 20 ; => raises an EX_NOVAR exception (undeclared variable "y") 
 +  echo "Not displayed"; this line will not appear in the console 
 +except 
 +  catch; => exits the program without error 
 +  echo "Exception"; this line will not appear in the console 
 +end 
 +</code> 
 +===== List of instructions ===== 
 +In alphabetical order 
 +===== Internal operation ===== 
 +The W source code is compiled into //p-code//.\\ 
 +This p-code is a series of elementary instructions specific to the W language.\\ 
 +It is the same program that analyzes the W source code and breaks it down into p-code instructions: 
 +  * in interpreted mode, the instructions are then executed directly 
 +  * in compiled mode, the instructions are written to the output assembler file. Finally, this assembler file is converted into binary, a digital translation of the p-code instructions. 
 +The p-code executor can also be called from another process, with p-code serving as a plugin-type language/library. A provided FastCGI module facilitates the use of W as a server-side language for websites. 
 + 
 +The binary format of p-code is big-endian, allowing the same W binary file to be used on any type of operating system and architecture. 
 + 
 +Expressions only concern variables of type Dynamic and Number and are managed in a stack using Reverse Polish Notation. 
 + 
 +List of instructions in W. 
 + 
 +Compilation rules for transforming W source code into p-code (W assembler).
  • en/presentation.1766594098.txt.gz
  • Dernière modification : 2025/12/24 16:34
  • de root