rust/src/comp/syntax/ast.rs

499 lines
13 KiB
Rust

// The Rust abstract syntax tree.
import option;
import codemap::{span, filename};
type spanned<T> = {node: T, span: span};
type ident = str;
// Functions may or may not have names.
type fn_ident = option::t<ident>;
// FIXME: with typestate constraint, could say
// idents and types are the same length, and are
// non-empty
type path_ = {global: bool, idents: [ident], types: [@ty]};
type path = spanned<path_>;
type crate_num = int;
type node_id = int;
type def_id = {crate: crate_num, node: node_id};
const local_crate: crate_num = 0;
const crate_node_id: node_id = 0;
tag ty_param_bound {
bound_copy;
bound_send;
bound_iface(@ty);
}
type ty_param = {ident: ident, id: node_id, bounds: @[ty_param_bound]};
tag def {
def_fn(def_id, purity);
def_obj_field(def_id, mutability);
def_self(def_id);
def_mod(def_id);
def_native_mod(def_id);
def_const(def_id);
def_arg(def_id, mode);
def_local(def_id, let_style);
def_variant(def_id /* tag */, def_id /* variant */);
def_ty(def_id);
def_ty_param(def_id, uint);
def_binding(def_id);
def_use(def_id);
def_native_ty(def_id);
def_native_fn(def_id, purity);
def_upvar(def_id, @def, node_id); // node_id == expr_fn or expr_fn_block
}
// The set of meta_items that define the compilation environment of the crate,
// used to drive conditional compilation
type crate_cfg = [@meta_item];
type crate = spanned<crate_>;
type crate_ =
{directives: [@crate_directive],
module: _mod,
attrs: [attribute],
config: crate_cfg};
tag crate_directive_ {
cdir_src_mod(ident, [attribute]);
cdir_dir_mod(ident, [@crate_directive], [attribute]);
// NB: cdir_view_item is *not* processed by the rest of the compiler; the
// attached view_items are sunk into the crate's module during parsing,
// and processed (resolved, imported, etc.) there. This tag-variant exists
// only to preserve the view items in order in case we decide to
// pretty-print crates in the future.
cdir_view_item(@view_item);
cdir_syntax(@path);
}
type crate_directive = spanned<crate_directive_>;
type meta_item = spanned<meta_item_>;
tag meta_item_ {
meta_word(ident);
meta_list(ident, [@meta_item]);
meta_name_value(ident, lit);
}
type blk = spanned<blk_>;
type blk_ = {view_items: [@view_item], stmts: [@stmt], expr: option::t<@expr>,
id: node_id, rules: blk_check_mode};
type pat = {id: node_id, node: pat_, span: span};
type field_pat = {ident: ident, pat: @pat};
tag pat_ {
pat_wild;
pat_bind(ident, option::t<@pat>);
pat_tag(@path, [@pat]);
pat_rec([field_pat], bool);
pat_tup([@pat]);
pat_box(@pat);
pat_uniq(@pat);
pat_lit(@expr);
pat_range(@expr, @expr);
}
tag mutability { mut; imm; maybe_mut; }
tag proto_sugar {
sugar_normal;
sugar_sexy;
}
tag proto {
proto_bare;
proto_send;
proto_shared(proto_sugar);
proto_block;
}
tag binop {
add;
sub;
mul;
div;
rem;
and;
or;
bitxor;
bitand;
bitor;
lsl;
lsr;
asr;
eq;
lt;
le;
ne;
ge;
gt;
}
tag unop {
box(mutability);
uniq(mutability);
deref; not; neg;
}
tag mode { by_ref; by_val; by_mut_ref; by_move; by_copy; mode_infer; }
type stmt = spanned<stmt_>;
tag stmt_ {
stmt_decl(@decl, node_id);
// expr without trailing semi-colon (must have unit type):
stmt_expr(@expr, node_id);
// expr with trailing semi-colon (may have any type):
stmt_semi(@expr, node_id);
}
tag init_op { init_assign; init_move; }
type initializer = {op: init_op, expr: @expr};
type local_ = // FIXME: should really be a refinement on pat
{ty: @ty, pat: @pat, init: option::t<initializer>, id: node_id};
type local = spanned<local_>;
type decl = spanned<decl_>;
tag let_style { let_copy; let_ref; }
tag decl_ { decl_local([(let_style, @local)]); decl_item(@item); }
type arm = {pats: [@pat], guard: option::t<@expr>, body: blk};
type field_ = {mut: mutability, ident: ident, expr: @expr};
type field = spanned<field_>;
tag blk_check_mode { default_blk; unchecked_blk; unsafe_blk; }
tag expr_check_mode { claimed_expr; checked_expr; }
type expr = {id: node_id, node: expr_, span: span};
tag expr_ {
expr_vec([@expr], mutability);
expr_rec([field], option::t<@expr>);
expr_call(@expr, [@expr], bool);
expr_tup([@expr]);
expr_bind(@expr, [option::t<@expr>]);
expr_binary(binop, @expr, @expr);
expr_unary(unop, @expr);
expr_lit(@lit);
expr_cast(@expr, @ty);
expr_if(@expr, blk, option::t<@expr>);
expr_ternary(@expr, @expr, @expr);
expr_while(@expr, blk);
expr_for(@local, @expr, blk);
expr_do_while(blk, @expr);
expr_alt(@expr, [arm]);
expr_fn(proto, fn_decl, blk, @capture_clause);
expr_fn_block(fn_decl, blk);
expr_block(blk);
/*
* FIXME: many of these @exprs should be constrained with
* is_lval once we have constrained types working.
*/
expr_copy(@expr);
expr_move(@expr, @expr);
expr_assign(@expr, @expr);
expr_swap(@expr, @expr);
expr_assign_op(binop, @expr, @expr);
expr_field(@expr, ident, [@ty]);
expr_index(@expr, @expr);
expr_path(@path);
expr_fail(option::t<@expr>);
expr_break;
expr_cont;
expr_ret(option::t<@expr>);
expr_be(@expr);
expr_log(int, @expr, @expr);
/* just an assert, no significance to typestate */
expr_assert(@expr);
/* preds that typestate is aware of */
expr_check(expr_check_mode, @expr);
/* FIXME Would be nice if expr_check desugared
to expr_if_check. */
expr_if_check(@expr, blk, option::t<@expr>);
expr_anon_obj(anon_obj);
expr_mac(mac);
}
type capture_item = {
id: int,
name: ident, // Currently, can only capture a local var.
span: span
};
type capture_clause = {
copies: [@capture_item],
moves: [@capture_item]
};
/*
// Says whether this is a block the user marked as
// "unchecked"
tag blk_sort {
blk_unchecked; // declared as "exception to effect-checking rules"
blk_checked; // all typing rules apply
}
*/
type mac = spanned<mac_>;
tag mac_ {
mac_invoc(@path, @expr, option::t<str>);
mac_embed_type(@ty);
mac_embed_block(blk);
mac_ellipsis;
}
type lit = spanned<lit_>;
tag lit_ {
lit_str(str);
lit_int(i64, int_ty);
lit_uint(u64, uint_ty);
lit_float(str, float_ty);
lit_nil;
lit_bool(bool);
}
// NB: If you change this, you'll probably want to change the corresponding
// type structure in middle/ty.rs as well.
type mt = {ty: @ty, mut: mutability};
type ty_field_ = {ident: ident, mt: mt};
type ty_field = spanned<ty_field_>;
type ty_method = {ident: ident, decl: fn_decl, tps: [ty_param], span: span};
tag int_ty { ty_i; ty_char; ty_i8; ty_i16; ty_i32; ty_i64; }
tag uint_ty { ty_u; ty_u8; ty_u16; ty_u32; ty_u64; }
tag float_ty { ty_f; ty_f32; ty_f64; }
type ty = spanned<ty_>;
tag ty_ {
ty_nil;
ty_bot; /* return type of ! functions and type of
ret/fail/break/cont. there is no syntax
for this type. */
/* bot represents the value of functions that don't return a value
locally to their context. in contrast, things like log that do
return, but don't return a meaningful value, have result type nil. */
ty_bool;
ty_int(int_ty);
ty_uint(uint_ty);
ty_float(float_ty);
ty_str;
ty_box(mt);
ty_uniq(mt);
ty_vec(mt);
ty_ptr(mt);
ty_task;
ty_port(@ty);
ty_chan(@ty);
ty_rec([ty_field]);
ty_fn(proto, fn_decl);
ty_obj([ty_method]);
ty_tup([@ty]);
ty_path(@path, node_id);
ty_type;
ty_constr(@ty, [@ty_constr]);
ty_mac(mac);
// ty_infer means the type should be inferred instead of it having been
// specified. This should only appear at the "top level" of a type and not
// nested in one.
ty_infer;
}
/*
A constraint arg that's a function argument is referred to by its position
rather than name. This is so we could have higher-order functions that have
constraints (potentially -- right now there's no way to write that), and also
so that the typestate pass doesn't have to map a function name onto its decl.
So, the constr_arg type is parameterized: it's instantiated with uint for
declarations, and ident for uses.
*/
tag constr_arg_general_<T> { carg_base; carg_ident(T); carg_lit(@lit); }
type fn_constr_arg = constr_arg_general_<uint>;
type sp_constr_arg<T> = spanned<constr_arg_general_<T>>;
type ty_constr_arg = sp_constr_arg<@path>;
type constr_arg = spanned<fn_constr_arg>;
// Constrained types' args are parameterized by paths, since
// we refer to paths directly and not by indices.
// The implicit root of such path, in the constraint-list for a
// constrained type, is * (referring to the base record)
type constr_general_<ARG, ID> =
{path: @path, args: [@spanned<constr_arg_general_<ARG>>], id: ID};
// In the front end, constraints have a node ID attached.
// Typeck turns this to a def_id, using the output of resolve.
type constr_general<ARG> = spanned<constr_general_<ARG, node_id>>;
type constr_ = constr_general_<uint, node_id>;
type constr = spanned<constr_general_<uint, node_id>>;
type ty_constr_ = constr_general_<@path, node_id>;
type ty_constr = spanned<ty_constr_>;
/* The parser generates ast::constrs; resolve generates
a mapping from each function to a list of ty::constr_defs,
corresponding to these. */
type arg = {mode: mode, ty: @ty, ident: ident, id: node_id};
type fn_decl =
{inputs: [arg],
output: @ty,
purity: purity,
cf: ret_style,
constraints: [@constr]};
tag purity {
pure_fn; // declared with "pure fn"
unsafe_fn; // declared with "unsafe fn"
impure_fn; // declared with "fn"
}
tag ret_style {
noreturn; // functions with return type _|_ that always
// raise an error or exit (i.e. never return to the caller)
return_val; // everything else
}
type method = {ident: ident, tps: [ty_param], decl: fn_decl, body: blk,
id: node_id, span: span};
type obj_field = {mut: mutability, ty: @ty, ident: ident, id: node_id};
type anon_obj_field =
{mut: mutability, ty: @ty, expr: @expr, ident: ident, id: node_id};
type _obj = {fields: [obj_field], methods: [@method]};
type anon_obj =
// New fields and methods, if they exist.
// inner_obj: the original object being extended, if it exists.
{fields: option::t<[anon_obj_field]>,
methods: [@method],
inner_obj: option::t<@expr>};
type _mod = {view_items: [@view_item], items: [@item]};
tag native_abi {
native_abi_rust_intrinsic;
native_abi_cdecl;
native_abi_stdcall;
}
type native_mod =
{view_items: [@view_item],
items: [@native_item]};
type variant_arg = {ty: @ty, id: node_id};
type variant_ = {name: ident, args: [variant_arg], id: node_id};
type variant = spanned<variant_>;
type view_item = spanned<view_item_>;
// FIXME: May want to just use path here, which would allow things like
// 'import ::foo'
type simple_path = [ident];
type import_ident_ = {name: ident, id: node_id};
type import_ident = spanned<import_ident_>;
tag view_item_ {
view_item_use(ident, [@meta_item], node_id);
view_item_import(ident, @simple_path, node_id);
view_item_import_glob(@simple_path, node_id);
view_item_import_from(@simple_path, [import_ident], node_id);
view_item_export([ident], node_id);
}
type obj_def_ids = {ty: node_id, ctor: node_id};
// Meta-data associated with an item
type attribute = spanned<attribute_>;
// Distinguishes between attributes that decorate items and attributes that
// are contained as statements within items. These two cases need to be
// distinguished for pretty-printing.
tag attr_style { attr_outer; attr_inner; }
type attribute_ = {style: attr_style, value: meta_item};
type item = // For objs and resources, this is the type def_id
{ident: ident, attrs: [attribute], id: node_id, node: item_, span: span};
tag item_ {
item_const(@ty, @expr);
item_fn(fn_decl, [ty_param], blk);
item_mod(_mod);
item_native_mod(native_mod);
item_ty(@ty, [ty_param]);
item_tag([variant], [ty_param]);
item_obj(_obj, [ty_param], /* constructor id */node_id);
item_res(fn_decl /* dtor */, [ty_param], blk,
node_id /* dtor id */, node_id /* ctor id */);
item_iface([ty_param], [ty_method]);
item_impl([ty_param], option::t<@ty> /* iface */,
@ty /* self */, [@method]);
}
type native_item =
{ident: ident,
attrs: [attribute],
node: native_item_,
id: node_id,
span: span};
tag native_item_ {
native_item_ty;
native_item_fn(fn_decl, [ty_param]);
}
//
// Local Variables:
// mode: rust
// fill-column: 78;
// indent-tabs-mode: nil
// c-basic-offset: 4
// buffer-file-coding-system: utf-8-unix
// End:
//