rune-langium / core/src / insertImplicitBrackets

Function: insertImplicitBrackets()

function insertImplicitBrackets(text): string;

Defined in: packages/core/src/services/rune-dsl-parser.ts:242

Scans Rune DSL source text and inserts [ and ] around bare expressions that follow extract, filter, or reduce operators.

Parameters

Parameter	Type	Description
text	string	Raw Rune DSL (.rosetta) source text.

Returns

string

Transformed text with implicit brackets inserted where needed.

Remarks

This is a pure text transformation applied before Chevrotain tokenization. It normalizes both forms — extract [body] (explicit) and extract expr (bare) — into the extract [body] form that the Langium grammar expects.

Algorithm:

1. Scan character-by-character, skipping strings and comments
2. When a functional operator keyword is found: a. Check if followed by [ — if so, skip (already InlineFunction) b. Check if followed by ID [ or ID , — if so, skip (closure param form) c. Otherwise, insert [ before the bare expression and ] at its end
3. Expression end is determined by tracking nesting depth and looking for terminators (comma, closing bracket, newline + statement keyword)

Multi-line support: when the keyword is at end of line (followed by newline + whitespace), we look at the next line. If it starts with an expression token (ID, (, -, +, etc.) and NOT a statement keyword, we treat the next line as the start of a bare expression.

Pitfalls

• The transformation is regex/character-scan based and cannot handle all edge cases in heavily nested multi-line expressions. When in doubt, use explicit [ ] brackets in your .rosetta source.
• Do NOT call this function on arbitrary text — it is designed specifically for Rune DSL (Rosetta) source and may corrupt non-Rosetta input.