qgis-syntax-expressions
Installation
SKILL.md
qgis-syntax-expressions
Quick Reference
Expression Evaluation Pipeline
| Step | Class | Purpose |
|---|---|---|
| 1. Parse | QgsExpression(string) |
Validate syntax, build AST |
| 2. Context | QgsExpressionContext() |
Provide variables, fields, scopes |
| 3. Scopes | QgsExpressionContextUtils |
Add global/project/layer/feature scopes |
| 4. Evaluate | exp.evaluate(context) |
Execute and return result |
| 5. Validate | exp.hasEvalError() |
Check for runtime errors |