Function parse_expression_str 

pub fn parse_expression_str(input: &str) -> ParseResult<Expr>

Parse one expression from source text with an empty module scope, for tooling that shows lowering without running (docs demos, explain output). No imports exist here, so bare function calls fail and qualified calls fail against the empty table; only INSPECT passes through untouched. Arithmetic, comparison, variables, env reads, keypaths, and literals lower normally, with literal only subtrees folded before flattening.