Modules¶

module	what it derives
`grammar`	the declaration itself, and every structural query
`lang_py`	Python's grammar: roles authored, sorts and shapes from `ast._field_types`
`lang_ssa`	a read-only mirror of a typed SSA IR, as evidence one notation covers both a tree and a flat IR
`rewriting`	the rule engine; `target_fields` gives `fix_contexts` its binding positions
`scopes`	the scope tree and the names each block binds, from roles plus a scope-layer list
`hygiene`	fresh names, renaming across every declared slot, capture-avoiding substitution
`coverage`	what a dispatch table covers of a grammar, and what it does not
`emit` / `emit_py`	documents, and brackets from a precedence table
`emit_rules`	emission as guarded rules over the grammar
`tables`	`Family`, for the tables no grammar derives
`generate`	programs exercising every declared position, with `missing_coverage` as the obligation

Entry points¶

from astero import Pass, Match, rules, rewrite      # the rule engine
from astero.grammar import Grammar, from_dataclasses, defines, uses, Present, Absent
from astero.lang_py import PY, VARS, build
from astero.scopes import scope_tree, bound_names
from astero.hygiene import substitute, rename, Fresh, free_names
from astero.coverage import Coverage, dispatch, handlers, match_arms
from astero.emit_rules import Emitter, All, Both, Either, Not, Is, OpIs, Const, Has
from astero.emit import Level, Assoc, needs_parens
from astero.tables import Family

Version sensitivity¶

_field_types is 3.13+, so on earlier interpreters shapes are UNKNOWN. Comprehensions stopped opening scopes in 3.12 (PEP 709). PEP 695 type-parameter blocks are spelled type parameter on 3.12 and type parameters from 3.13. PEP 649 adds annotation blocks from 3.14. symtable.get_type() returns a string before 3.13 and an enum after.

astero is tested on 3.11 through 3.15.