Compiler Foundations

Overview

An expression front-end in quantsmind.compiler: lexer, recursive-descent parser, AST nodes, constant folding, and tree evaluation. Deliberately a front-end for arithmetic expressions — not a programming language.

Purpose

Let users tokenize, parse, transform, and evaluate SDK expressions with positioned diagnostics, independent of any backend.

Concept

tokenize() yields Tokens; Parser/parse() builds Number, Name, UnaryOp, BinOp trees; fold_constants() shrinks constant subtrees; evaluate() resolves names against an environment dict. LexError, ParseError, and EvaluationError carry positions.

API

tokenize(), Token, LexError, parse(), Parser, ParseError, Number, Name, UnaryOp, BinOp, node_count(), to_dict(), evaluate(), fold_constants(), EvaluationError.

Input / Processing / Output

Input: expression strings. Processing: lex → parse → fold → eval. Output: values, smaller trees, JSON-safe dicts.

Example

python examples/compiler/expr_eval.py runs "2 + 3 * x" end to end.

Limitations

Arithmetic only (no functions, no assignment); no bytecode or machine targets; division by zero and unbound names are runtime errors by design.