Module expr_parse 

SQL expression text → SqlExpr AST parser.

Parses the subset of SQL expressions used in GENERATED ALWAYS AS (expr) column definitions. Supports:

• Column references: price, tax_rate
• Numeric literals: 42, 3.14, -1
• String literals: 'hello', ''escaped''
• Binary operators: +, -, *, /, %
• Comparison: =, !=, <>, <, >, <=, >=
• Logical: AND, OR, NOT
• Parenthesized sub-expressions: (a + b) * c
• Function calls: ROUND(price * 1.08, 2), CONCAT(a, ' ', b)
• COALESCE: COALESCE(a, b, '')
• CASE WHEN: CASE WHEN x > 0 THEN 'positive' ELSE 'non-positive' END
• NULL literal

Determinism validation: rejects NOW(), RANDOM(), NEXTVAL(), UUID().

Functions

parse_generated_expr

Parse a SQL expression string into an SqlExpr AST.