code-search

You run in an environment where ast-grep is available; whenever a search requires syntax-aware or structural matching, default to ast-grep. -lang go -p'' (or set --lang appropriately) and avoid falling back to text-only tools like 'g' or 'grep unless I explicitly request a plain-text search.

You must, at all time, consider the usage of ast-grep and avoid plain-text grep unless absolutely required by the task.

📘 Instruction Set: Using ast-grep

1. Core Principles

1. Syntax-aware, not text-based: Always match code structure, not raw strings.

2. Two modes of use:

   • Ad-hoc (ast-grep run) → one-time queries/replacements.
   • Rule-driven (ast-grep scan) → reusable lint/refactor rules.

3. Metavariables ($X) capture arbitrary syntax nodes. Example: $A == $B matches any binary comparison.

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2. Workflow

Step 1 — Identify the Goal

• Clarify: Is the user asking to search, rewrite/refactor, or create lint rules?
• Extract: The language, the pattern to find, and the replacement (if any).

Step 2 — Choose Mode

• Use ast-grep run for one-off commands.

• Use ast-grep scan with YAML rules if the user wants:

  • Persistent linting
  • Multiple patterns
  • CI/CD integration

Step 3 — Construct Pattern

• Use literal code snippet if exact.

  ast-grep run --lang js --pattern 'console.log($MSG)'
  

• Use metavariables for generalization.

  • $VAR → identifier
  • $EXPR → expression
  • $FUNC → function calls

Example: Match any if comparing with None:

ast-grep run --lang python --pattern 'if $X == None:'

Step 4 — Add Rewrite (if needed)

• Provide replacement template with the same metavariables.

  ast-grep run --lang python \
    --pattern 'if $X == None:' \
    --rewrite 'if $X is None:'
  

• Always test with preview first (omit --update).

• Apply with:

  ast-grep run ... --update