Provisional API: This reference documents current compiler behavior. Compatibility is not yet promised.

`src/ast.x`

Shared helpers for x2c compiler AST nodes.

Functions

Function	Summary
`Ast.addressed_identifier`	Returns the name whose address an expression takes, or `NULL`.
`Ast.append_modifiers`	Returns `declarator` with `modifiers` after its own, as a declaration whose base contributes modifiers declares each name.
`Ast.binding`	Constructs a `(binding identity spelling)` node.
`Ast.binding_spelling`	Returns a valid binding node’s source spelling, or `NULL`.
`Ast.collect_binding_references`	Records in `referenced` the identity of every binding `node` names.
`Ast.contains_head`	Returns whether any list under `value` has `kind` as its head.
`Ast.designated`	Returns the innermost node `value` designates, past the forms that still name the same object: an `expr` wrapper, parentheses, a member, and an index into an array.
`Ast.direct_identifier`	Returns the name an expression designates directly, following the forms that still name the same object - parentheses, a member, an array index, a dereference - or `NULL` when the expression designates no single name.
`Ast.entry_call`	Returns the statement calling the `void (void)` function `entry`.
`Ast.indirect_identifier`	Returns the name of the pointer an expression designates through, or `NULL` when it designates no object through a single name.
`Ast.initializer_cases`	Returns initializer alternatives and their optional native macro input.
`Ast.initializer_functions`	Returns function alternatives when every initializer arm calls one shared input, and stores that input expression in `source`.
`Ast.lvalue_binding`	Returns the binding whose stored object the lvalue `ast` names, or `NULL`.
`Ast.never_returns`	Returns whether control cannot flow out the bottom of `ast`.
`Ast.prototype_declarator`	Returns `declarator` with the outermost `volatile` removed from each of its parameters.
`Ast.reference_guard_exits`	Returns whether `arm` ends with a return or non-returning raise.
`Ast.replace_nodes`	Returns `root` with each list beneath it that `replaced` maps, keyed by its address, swapped for its value, and adds each rebuilt ancestor to `replaced`.
`Ast.rewrap_origin`	Returns `replacement` under the anchors of `original`, the statement it replaces, so a rewrite does not lose the node’s source position.
`Ast.rewrite_children`	Applies `per_child` to each `List` child of `ast` and returns the node rebuilt from the results; non-list children pass through.
`Ast.try_binding`	Extracts a valid `(binding positive-integer string)` node.
`Ast.without_origin`	Returns `ast` without the `(at ORIGIN ...)` anchors it arrived wrapped in.
`Ast.written_definitions`	Returns `decl` with each function definition marked `kernel` as written.
`Ast.written_operand`	Returns the operand a write `node` changes: the left operand of an assignment or prefix update, or the operand of a postfix update; `NULL` when `node` writes no operand.
`Symbol.changes_left_operand`	Returns whether `op` writes its left operand.
`Symbol.is_assignment_op`	Returns whether `op` is plain or compound assignment.

`Ast`

Ast.addressed_identifier

String Ast.addressed_identifier(Var value)

Returns the name whose address an expression takes, or NULL.

Source: src/ast.x:141

Ast.append_modifiers

List Ast.append_modifiers(List declarator, List modifiers)

Returns declarator with modifiers after its own, as a declaration whose base contributes modifiers declares each name.

Source: src/ast.x:59

Ast.binding

List Ast.binding(int identity, String spelling)

Constructs a (binding identity spelling) node. The caller must supply a positive compiler-issued identity.

Source: src/ast.x:30

Ast.binding_spelling

String Ast.binding_spelling(List binding)

Returns a valid binding node’s source spelling, or NULL.

Source: src/ast.x:50

Ast.collect_binding_references

void Ast.collect_binding_references(Var node, Map referenced)

Records in referenced the identity of every binding node names.

Source: src/ast.x:256

Ast.contains_head

int Ast.contains_head(Var value, Symbol kind)

Returns whether any list under value has kind as its head.

Source: src/ast.x:218

Returns the innermost node value designates, past the forms that still name the same object: an expr wrapper, parentheses, a member, and an index into an array. What remains is a name, a designation through a pointer, or another expression; a non-list designates nothing.

Source: src/ast.x:114

Ast.direct_identifier

String Ast.direct_identifier(Var value)

Returns the name an expression designates directly, following the forms that still name the same object - parentheses, a member, an array index, a dereference - or NULL when the expression designates no single name. A declaration qualifier that must reach one object, such as the volatile an error transfer requires, applies to this name.

Source: src/ast.x:160

Ast.entry_call

List Ast.entry_call(String entry)

Returns the statement calling the void (void) function entry.

Source: src/ast.x:310

Ast.indirect_identifier

String Ast.indirect_identifier(Var value)

Returns the name of the pointer an expression designates through, or NULL when it designates no object through a single name. *pointer, pointer[index], and pointer->member all change the object the pointer holds, which Ast.direct_identifier reports as no name at all.

Source: src/ast.x:178

Ast.initializer_cases

List Ast.initializer_cases(Ast ast, List &input)

Returns initializer alternatives and their optional native macro input.

Source: src/ast.x:388

Ast.initializer_functions

List Ast.initializer_functions(Ast ast, List &source)

Returns function alternatives when every initializer arm calls one shared input, and stores that input expression in source. Other forms return NULL.

Source: src/ast.x:402

Ast.lvalue_binding

List Ast.lvalue_binding(Ast ast)

Returns the binding whose stored object the lvalue ast names, or NULL. Pointer dereferences and pointer indexes name another object; an array field remains part of its containing aggregate.

Source: src/ast.x:133

Ast.never_returns

int Ast.never_returns(Ast ast)

Returns whether control cannot flow out the bottom of ast. Recognized terminals are shared non-returning raises, native termination calls, and blocks ending in either one when the block contains no return. Generation uses this fact to mark the enclosing function _Noreturn.

Source: src/ast.x:335

Ast.prototype_declarator

List Ast.prototype_declarator(List declarator)

Returns declarator with the outermost volatile removed from each of its parameters. C ignores a parameter’s top-level qualifier when it compares a prototype with its definition, and the qualifier the error transfer requires belongs to the definition that writes the parameter, not to the declaration its callers read.

Source: src/ast.x:77

Ast.reference_guard_exits

int Ast.reference_guard_exits(List arm)

Returns whether arm ends with a return or non-returning raise.

Source: src/ast.x:316

Ast.replace_nodes

Var Ast.replace_nodes(Var root, Map replaced)

Returns root with each list beneath it that replaced maps, keyed by its address, swapped for its value, and adds each rebuilt ancestor to replaced. Only the ancestors of a swapped list are new, so root returns itself when nothing beneath it is swapped. The walk keeps deep expression chains off the C stack.

Source: src/ast.x:229

Ast.rewrap_origin

Ast Ast.rewrap_origin(Ast original, Ast replacement)

Returns replacement under the anchors of original, the statement it replaces, so a rewrite does not lose the node’s source position.

Source: src/ast.x:288

Ast.rewrite_children

Ast Ast.rewrite_children(Ast ast, Func per_child)

Applies per_child to each List child of ast and returns the node rebuilt from the results; non-list children pass through. When no child changed, no scratch storage is allocated and ast itself returns, so the fixed-point transform driver can compare unchanged-node identity.

Source: src/ast.x:212

Ast.try_binding

int Ast.try_binding( List binding, int &?identity, String &?spelling)

Extracts a valid (binding positive-integer string) node. Returns one on success and writes only non-NULL outputs; failure returns zero without changing either output.

Source: src/ast.x:37

Ast.without_origin

Ast Ast.without_origin(Ast ast)

Returns ast without the (at ORIGIN ...) anchors it arrived wrapped in. Every block statement carries one so that a transform-phase diagnostic can name its line; a pass that dispatches on a statement tag has to see the statement, not the anchor.

Source: src/ast.x:276

Ast.written_definitions

List Ast.written_definitions(List decl)

Returns decl with each function definition marked kernel as written. The transform strips the marker before it offers the definition only to shipped function rules.

Source: src/ast.x:300

Ast.written_operand

List Ast.written_operand(Ast node)

Returns the operand a write node changes: the left operand of an assignment or prefix update, or the operand of a postfix update; NULL when node writes no operand.

Source: src/ast.x:195