SPG SQL front-end. v0.2 ships only the lexer + a minimal recursive-descent
parser for the SELECT [..] FROM [..] WHERE [..] subset.
Layers (each in its own module):
- [
lexer] — byte stream → tokens - [
ast] — abstract syntax tree types +Display(pretty-print) - [
parser] — tokens → AST (Pratt parser for expression precedence)