CIE 9618 Pseudocode

Syntax highlighting for Cambridge International AS & A Level Computer Science (9618) pseudocode in Visual Studio Code.

Write your pseudocode in an editor that makes it look and feel like a real language: coloured keywords, snippets, auto-indentation and code folding.

This extension is for visuals only. It does not run, interpret, compile or debug pseudocode. Files such as .psc or .pseudo can be highlighted and edited, but they cannot be executed.

Features

• Syntax highlighting for the pseudocode conventions in the 9618 Pseudocode Guide for Teachers:
  • Selection and iteration: IF, ELSE, CASE OF, FOR, WHILE, REPEAT
  • Declarations: DECLARE, CONSTANT, TYPE, DEFINE, arrays, records, enumerated, pointer and set types
  • Procedures and functions: PROCEDURE, FUNCTION, CALL, RETURN, BYVAL, BYREF
  • File handling: OPENFILE, READFILE, WRITEFILE, SEEK, GETRECORD, PUTRECORD, CLOSEFILE
  • Object-oriented programming: CLASS, INHERITS, PUBLIC, PRIVATE, NEW, SUPER
  • Built-in functions: LENGTH, MID, RIGHT, LCASE, UCASE, INT, RAND, EOF
  • Data types, string, char, date and numeric literals, // comments
  • Operators including ← (and <-), DIV, MOD, &, AND, OR, NOT
• Snippets for common structures. Type for, while, repeat, case, procedure, function, array, record, class, readfile and so on, then press Tab.
• Auto-indent and folding for blocks such as IF ... ENDIF and FOR ... NEXT.
• Tab size defaults to 3 spaces for pseudocode files, matching the guide.

Supported file extensions

.psc, .pseudo, .pseudocode

You can also select CIE 9618 Pseudocode from the language picker at the bottom right of VS Code for any file.

Notes

• Keywords are highlighted in UPPER CASE only, as the guide specifies. A lower-case if will not be coloured, which helps catch mistakes.
• <- is highlighted the same as ←, so you can type it quickly.
• Highlighting is based on patterns, so unusual or partial code may not always colour perfectly.

Limitations

• No execution, interpreter, debugger or output panel.
• No error checking, type checking or auto-completion of your own variables and procedures.
• Colours depend on your VS Code colour theme.

Disclaimer

This is an independent, community-made extension. It is not affiliated with, endorsed by, or sponsored by Cambridge University Press & Assessment or Cambridge International Education. "Cambridge" and "9618" are used only to describe the pseudocode style the extension supports. The pseudocode conventions follow the publicly available Pseudocode Guide for Teachers for exams in 2026; always check the official syllabus and guide for the latest rules.

Feedback

Found a construct that isn't highlighted correctly? Please open an issue with a short code sample.

Release notes

0.1.0

• Initial release: syntax highlighting, snippets, indentation and folding.