The CAIE pseudocode web interpreter

Provides an online web editor for CAIE Pseudocode, with syntax highlighting, and a javascript-based interpreter for the language. Website URL: The web interpreter The code I written is quite low quality, so try not to go very deep into the code.

Syntax

Below are some basic examples of the syntax of the language.

1. Variable declaration

   DECLARE <Identifier>: <Type>
   

2. Variable assignment

   <Identifier> <- <Expression>
   

3. Array declaration

   DECLARE <Identifier>: ARRAY[0:<Size>] OF <Type>
   

4. Array assignment

   <Identifier>[<Index>] <- <Expression>
   

5. If statement

   IF <Expression> THEN
       <Statements>
   ELSE
       <Statements>
   ENDIF
   

6. While loop

   WHILE <Expression>
       <Statements>
   ENDWHILE
   

7. For loop

   FOR <Identifier> <- <Expression> TO <Expression>
       <Statements>
   ENDFOR
   

8. Output statement

   OUTPUT <Expression>
   

9. Comments

   // This is a comment
   

Features to implement

• Functions & Procedures
• Struct & Pointer
• Optimise the interpreter
• File operations

Some differences from the original CAIE pseudocode

• Only supports Array with the lower boundary of 0. (e.g. ARRAY[0:10] OF INTEGER) Personally I think it is stupid to start an array from non-zero index.

Interpreter

The interpreter is written in pure front-end (everything is imported by CDN, I know it is shit) javascript (will be a backend version in the future). It is simply a tree-walk interpreter using LL(1) parsing, with a few optimizations. The interpreter is not very efficient, and is not intended for production use. It is only intended for educational purposes. The editor uses the monaco editor for the editing system and uses xterm.js to setup a fake terminal for the IO system. Element-ui is also used for layout.

Contributing

Contributions are welcome. Please open a a pull request if you would like to contribute. You are also welcome to give your own test samples. (If you found any bugs or have any suggestions, you're welcome to open an issue.)

Ps: Most of this README.md is written by copilot. So it is likely to be a piece of shit.