rust/src/libsyntax/ast_util.rs
2014-12-19 10:51:00 -05:00

801 lines
23 KiB
Rust

// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use abi::Abi;
use ast::*;
use ast;
use ast_util;
use codemap;
use codemap::Span;
use owned_slice::OwnedSlice;
use parse::token;
use print::pprust;
use ptr::P;
use visit::Visitor;
use visit;
use std::cmp;
use std::u32;
pub fn path_name_i(idents: &[Ident]) -> String {
// FIXME: Bad copies (#2543 -- same for everything else that says "bad")
idents.iter().map(|i| {
token::get_ident(*i).get().to_string()
}).collect::<Vec<String>>().connect("::")
}
pub fn local_def(id: NodeId) -> DefId {
ast::DefId { krate: LOCAL_CRATE, node: id }
}
pub fn is_local(did: ast::DefId) -> bool { did.krate == LOCAL_CRATE }
pub fn stmt_id(s: &Stmt) -> NodeId {
match s.node {
StmtDecl(_, id) => id,
StmtExpr(_, id) => id,
StmtSemi(_, id) => id,
StmtMac(..) => panic!("attempted to analyze unexpanded stmt")
}
}
pub fn binop_to_string(op: BinOp) -> &'static str {
match op {
BiAdd => "+",
BiSub => "-",
BiMul => "*",
BiDiv => "/",
BiRem => "%",
BiAnd => "&&",
BiOr => "||",
BiBitXor => "^",
BiBitAnd => "&",
BiBitOr => "|",
BiShl => "<<",
BiShr => ">>",
BiEq => "==",
BiLt => "<",
BiLe => "<=",
BiNe => "!=",
BiGe => ">=",
BiGt => ">"
}
}
pub fn lazy_binop(b: BinOp) -> bool {
match b {
BiAnd => true,
BiOr => true,
_ => false
}
}
pub fn is_shift_binop(b: BinOp) -> bool {
match b {
BiShl => true,
BiShr => true,
_ => false
}
}
/// Returns `true` if the binary operator takes its arguments by value
pub fn is_by_value_binop(b: BinOp) -> bool {
match b {
BiAdd | BiSub | BiMul | BiDiv | BiRem | BiBitXor | BiBitAnd | BiBitOr | BiShl | BiShr => {
true
}
_ => false
}
}
/// Returns `true` if the unary operator takes its argument by value
pub fn is_by_value_unop(u: UnOp) -> bool {
match u {
UnNeg | UnNot => true,
_ => false,
}
}
pub fn unop_to_string(op: UnOp) -> &'static str {
match op {
UnUniq => "box() ",
UnDeref => "*",
UnNot => "!",
UnNeg => "-",
}
}
pub fn is_path(e: P<Expr>) -> bool {
return match e.node { ExprPath(_) => true, _ => false };
}
/// Get a string representation of a signed int type, with its value.
/// We want to avoid "45int" and "-3int" in favor of "45" and "-3"
pub fn int_ty_to_string(t: IntTy, val: Option<i64>) -> String {
let s = match t {
TyI if val.is_some() => "i",
TyI => "int",
TyI8 => "i8",
TyI16 => "i16",
TyI32 => "i32",
TyI64 => "i64"
};
match val {
// cast to a u64 so we can correctly print INT64_MIN. All integral types
// are parsed as u64, so we wouldn't want to print an extra negative
// sign.
Some(n) => format!("{}{}", n as u64, s),
None => s.to_string()
}
}
pub fn int_ty_max(t: IntTy) -> u64 {
match t {
TyI8 => 0x80u64,
TyI16 => 0x8000u64,
TyI | TyI32 => 0x80000000u64, // actually ni about TyI
TyI64 => 0x8000000000000000u64
}
}
/// Get a string representation of an unsigned int type, with its value.
/// We want to avoid "42uint" in favor of "42u"
pub fn uint_ty_to_string(t: UintTy, val: Option<u64>) -> String {
let s = match t {
TyU if val.is_some() => "u",
TyU => "uint",
TyU8 => "u8",
TyU16 => "u16",
TyU32 => "u32",
TyU64 => "u64"
};
match val {
Some(n) => format!("{}{}", n, s),
None => s.to_string()
}
}
pub fn uint_ty_max(t: UintTy) -> u64 {
match t {
TyU8 => 0xffu64,
TyU16 => 0xffffu64,
TyU | TyU32 => 0xffffffffu64, // actually ni about TyU
TyU64 => 0xffffffffffffffffu64
}
}
pub fn float_ty_to_string(t: FloatTy) -> String {
match t {
TyF32 => "f32".to_string(),
TyF64 => "f64".to_string(),
}
}
// convert a span and an identifier to the corresponding
// 1-segment path
pub fn ident_to_path(s: Span, identifier: Ident) -> Path {
ast::Path {
span: s,
global: false,
segments: vec!(
ast::PathSegment {
identifier: identifier,
parameters: ast::AngleBracketedParameters(ast::AngleBracketedParameterData {
lifetimes: Vec::new(),
types: OwnedSlice::empty(),
bindings: OwnedSlice::empty(),
})
}
),
}
}
// If path is a single segment ident path, return that ident. Otherwise, return
// None.
pub fn path_to_ident(path: &Path) -> Option<Ident> {
if path.segments.len() != 1 {
return None;
}
let segment = &path.segments[0];
if !segment.parameters.is_empty() {
return None;
}
Some(segment.identifier)
}
pub fn ident_to_pat(id: NodeId, s: Span, i: Ident) -> P<Pat> {
P(Pat {
id: id,
node: PatIdent(BindByValue(MutImmutable), codemap::Spanned{span:s, node:i}, None),
span: s
})
}
pub fn name_to_dummy_lifetime(name: Name) -> Lifetime {
Lifetime { id: DUMMY_NODE_ID,
span: codemap::DUMMY_SP,
name: name }
}
/// Generate a "pretty" name for an `impl` from its type and trait.
/// This is designed so that symbols of `impl`'d methods give some
/// hint of where they came from, (previously they would all just be
/// listed as `__extensions__::method_name::hash`, with no indication
/// of the type).
pub fn impl_pretty_name(trait_ref: &Option<TraitRef>, ty: &Ty) -> Ident {
let mut pretty = pprust::ty_to_string(ty);
match *trait_ref {
Some(ref trait_ref) => {
pretty.push('.');
pretty.push_str(pprust::path_to_string(&trait_ref.path).as_slice());
}
None => {}
}
token::gensym_ident(pretty.as_slice())
}
pub fn trait_method_to_ty_method(method: &Method) -> TypeMethod {
match method.node {
MethDecl(ident,
ref generics,
abi,
ref explicit_self,
unsafety,
ref decl,
_,
vis) => {
TypeMethod {
ident: ident,
attrs: method.attrs.clone(),
unsafety: unsafety,
decl: (*decl).clone(),
generics: generics.clone(),
explicit_self: (*explicit_self).clone(),
id: method.id,
span: method.span,
vis: vis,
abi: abi,
}
},
MethMac(_) => panic!("expected non-macro method declaration")
}
}
/// extract a TypeMethod from a TraitItem. if the TraitItem is
/// a default, pull out the useful fields to make a TypeMethod
//
// NB: to be used only after expansion is complete, and macros are gone.
pub fn trait_item_to_ty_method(method: &TraitItem) -> TypeMethod {
match *method {
RequiredMethod(ref m) => (*m).clone(),
ProvidedMethod(ref m) => trait_method_to_ty_method(&**m),
TypeTraitItem(_) => {
panic!("trait_method_to_ty_method(): expected method but found \
typedef")
}
}
}
pub fn split_trait_methods(trait_methods: &[TraitItem])
-> (Vec<TypeMethod>, Vec<P<Method>> ) {
let mut reqd = Vec::new();
let mut provd = Vec::new();
for trt_method in trait_methods.iter() {
match *trt_method {
RequiredMethod(ref tm) => reqd.push((*tm).clone()),
ProvidedMethod(ref m) => provd.push((*m).clone()),
TypeTraitItem(_) => {}
}
};
(reqd, provd)
}
pub fn struct_field_visibility(field: ast::StructField) -> Visibility {
match field.node.kind {
ast::NamedField(_, v) | ast::UnnamedField(v) => v
}
}
/// Maps a binary operator to its precedence
pub fn operator_prec(op: ast::BinOp) -> uint {
match op {
// 'as' sits here with 12
BiMul | BiDiv | BiRem => 11u,
BiAdd | BiSub => 10u,
BiShl | BiShr => 9u,
BiBitAnd => 8u,
BiBitXor => 7u,
BiBitOr => 6u,
BiLt | BiLe | BiGe | BiGt => 4u,
BiEq | BiNe => 3u,
BiAnd => 2u,
BiOr => 1u
}
}
/// Precedence of the `as` operator, which is a binary operator
/// not appearing in the prior table.
#[allow(non_upper_case_globals)]
pub static as_prec: uint = 12u;
pub fn empty_generics() -> Generics {
Generics {
lifetimes: Vec::new(),
ty_params: OwnedSlice::empty(),
where_clause: WhereClause {
id: DUMMY_NODE_ID,
predicates: Vec::new(),
}
}
}
// ______________________________________________________________________
// Enumerating the IDs which appear in an AST
#[deriving(Copy, Encodable, Decodable, Show)]
pub struct IdRange {
pub min: NodeId,
pub max: NodeId,
}
impl IdRange {
pub fn max() -> IdRange {
IdRange {
min: u32::MAX,
max: u32::MIN,
}
}
pub fn empty(&self) -> bool {
self.min >= self.max
}
pub fn add(&mut self, id: NodeId) {
self.min = cmp::min(self.min, id);
self.max = cmp::max(self.max, id + 1);
}
}
pub trait IdVisitingOperation {
fn visit_id(&mut self, node_id: NodeId);
}
/// A visitor that applies its operation to all of the node IDs
/// in a visitable thing.
pub struct IdVisitor<'a, O:'a> {
pub operation: &'a mut O,
pub pass_through_items: bool,
pub visited_outermost: bool,
}
impl<'a, O: IdVisitingOperation> IdVisitor<'a, O> {
fn visit_generics_helper(&mut self, generics: &Generics) {
for type_parameter in generics.ty_params.iter() {
self.operation.visit_id(type_parameter.id)
}
for lifetime in generics.lifetimes.iter() {
self.operation.visit_id(lifetime.lifetime.id)
}
}
}
impl<'a, 'v, O: IdVisitingOperation> Visitor<'v> for IdVisitor<'a, O> {
fn visit_mod(&mut self,
module: &Mod,
_: Span,
node_id: NodeId) {
self.operation.visit_id(node_id);
visit::walk_mod(self, module)
}
fn visit_view_item(&mut self, view_item: &ViewItem) {
if !self.pass_through_items {
if self.visited_outermost {
return;
} else {
self.visited_outermost = true;
}
}
match view_item.node {
ViewItemExternCrate(_, _, node_id) => {
self.operation.visit_id(node_id)
}
ViewItemUse(ref view_path) => {
match view_path.node {
ViewPathSimple(_, _, node_id) |
ViewPathGlob(_, node_id) => {
self.operation.visit_id(node_id)
}
ViewPathList(_, ref paths, node_id) => {
self.operation.visit_id(node_id);
for path in paths.iter() {
self.operation.visit_id(path.node.id())
}
}
}
}
}
visit::walk_view_item(self, view_item);
self.visited_outermost = false;
}
fn visit_foreign_item(&mut self, foreign_item: &ForeignItem) {
self.operation.visit_id(foreign_item.id);
visit::walk_foreign_item(self, foreign_item)
}
fn visit_item(&mut self, item: &Item) {
if !self.pass_through_items {
if self.visited_outermost {
return
} else {
self.visited_outermost = true
}
}
self.operation.visit_id(item.id);
if let ItemEnum(ref enum_definition, _) = item.node {
for variant in enum_definition.variants.iter() {
self.operation.visit_id(variant.node.id)
}
}
visit::walk_item(self, item);
self.visited_outermost = false
}
fn visit_local(&mut self, local: &Local) {
self.operation.visit_id(local.id);
visit::walk_local(self, local)
}
fn visit_block(&mut self, block: &Block) {
self.operation.visit_id(block.id);
visit::walk_block(self, block)
}
fn visit_stmt(&mut self, statement: &Stmt) {
self.operation.visit_id(ast_util::stmt_id(statement));
visit::walk_stmt(self, statement)
}
fn visit_pat(&mut self, pattern: &Pat) {
self.operation.visit_id(pattern.id);
visit::walk_pat(self, pattern)
}
fn visit_expr(&mut self, expression: &Expr) {
self.operation.visit_id(expression.id);
visit::walk_expr(self, expression)
}
fn visit_ty(&mut self, typ: &Ty) {
self.operation.visit_id(typ.id);
if let TyPath(_, id) = typ.node {
self.operation.visit_id(id);
}
visit::walk_ty(self, typ)
}
fn visit_generics(&mut self, generics: &Generics) {
self.visit_generics_helper(generics);
visit::walk_generics(self, generics)
}
fn visit_fn(&mut self,
function_kind: visit::FnKind<'v>,
function_declaration: &'v FnDecl,
block: &'v Block,
span: Span,
node_id: NodeId) {
if !self.pass_through_items {
match function_kind {
visit::FkMethod(..) if self.visited_outermost => return,
visit::FkMethod(..) => self.visited_outermost = true,
_ => {}
}
}
self.operation.visit_id(node_id);
match function_kind {
visit::FkItemFn(_, generics, _, _) |
visit::FkMethod(_, generics, _) => {
self.visit_generics_helper(generics)
}
visit::FkFnBlock => {}
}
for argument in function_declaration.inputs.iter() {
self.operation.visit_id(argument.id)
}
visit::walk_fn(self,
function_kind,
function_declaration,
block,
span);
if !self.pass_through_items {
if let visit::FkMethod(..) = function_kind {
self.visited_outermost = false;
}
}
}
fn visit_struct_field(&mut self, struct_field: &StructField) {
self.operation.visit_id(struct_field.node.id);
visit::walk_struct_field(self, struct_field)
}
fn visit_struct_def(&mut self,
struct_def: &StructDef,
_: ast::Ident,
_: &ast::Generics,
id: NodeId) {
self.operation.visit_id(id);
struct_def.ctor_id.map(|ctor_id| self.operation.visit_id(ctor_id));
visit::walk_struct_def(self, struct_def);
}
fn visit_trait_item(&mut self, tm: &ast::TraitItem) {
match *tm {
ast::RequiredMethod(ref m) => self.operation.visit_id(m.id),
ast::ProvidedMethod(ref m) => self.operation.visit_id(m.id),
ast::TypeTraitItem(ref typ) => self.operation.visit_id(typ.ty_param.id),
}
visit::walk_trait_item(self, tm);
}
fn visit_lifetime_ref(&mut self, lifetime: &'v Lifetime) {
self.operation.visit_id(lifetime.id);
}
fn visit_lifetime_def(&mut self, def: &'v LifetimeDef) {
self.visit_lifetime_ref(&def.lifetime);
}
}
pub fn visit_ids_for_inlined_item<O: IdVisitingOperation>(item: &InlinedItem,
operation: &mut O) {
let mut id_visitor = IdVisitor {
operation: operation,
pass_through_items: true,
visited_outermost: false,
};
visit::walk_inlined_item(&mut id_visitor, item);
}
struct IdRangeComputingVisitor {
result: IdRange,
}
impl IdVisitingOperation for IdRangeComputingVisitor {
fn visit_id(&mut self, id: NodeId) {
self.result.add(id);
}
}
pub fn compute_id_range_for_inlined_item(item: &InlinedItem) -> IdRange {
let mut visitor = IdRangeComputingVisitor {
result: IdRange::max()
};
visit_ids_for_inlined_item(item, &mut visitor);
visitor.result
}
/// Computes the id range for a single fn body, ignoring nested items.
pub fn compute_id_range_for_fn_body(fk: visit::FnKind,
decl: &FnDecl,
body: &Block,
sp: Span,
id: NodeId)
-> IdRange
{
let mut visitor = IdRangeComputingVisitor {
result: IdRange::max()
};
let mut id_visitor = IdVisitor {
operation: &mut visitor,
pass_through_items: false,
visited_outermost: false,
};
id_visitor.visit_fn(fk, decl, body, sp, id);
id_visitor.operation.result
}
// FIXME(#19596) unbox `it`
pub fn walk_pat(pat: &Pat, it: |&Pat| -> bool) -> bool {
if !it(pat) {
return false;
}
match pat.node {
PatIdent(_, _, Some(ref p)) => walk_pat(&**p, it),
PatStruct(_, ref fields, _) => {
fields.iter().all(|field| walk_pat(&*field.node.pat, |p| it(p)))
}
PatEnum(_, Some(ref s)) | PatTup(ref s) => {
s.iter().all(|p| walk_pat(&**p, |p| it(p)))
}
PatBox(ref s) | PatRegion(ref s) => {
walk_pat(&**s, it)
}
PatVec(ref before, ref slice, ref after) => {
before.iter().all(|p| walk_pat(&**p, |p| it(p))) &&
slice.iter().all(|p| walk_pat(&**p, |p| it(p))) &&
after.iter().all(|p| walk_pat(&**p, |p| it(p)))
}
PatMac(_) => panic!("attempted to analyze unexpanded pattern"),
PatWild(_) | PatLit(_) | PatRange(_, _) | PatIdent(_, _, _) |
PatEnum(_, _) => {
true
}
}
}
pub trait EachViewItem {
fn each_view_item<F>(&self, f: F) -> bool where F: FnMut(&ast::ViewItem) -> bool;
}
struct EachViewItemData<F> where F: FnMut(&ast::ViewItem) -> bool {
callback: F,
}
impl<'v, F> Visitor<'v> for EachViewItemData<F> where F: FnMut(&ast::ViewItem) -> bool {
fn visit_view_item(&mut self, view_item: &ast::ViewItem) {
let _ = (self.callback)(view_item);
}
}
impl EachViewItem for ast::Crate {
fn each_view_item<F>(&self, f: F) -> bool where F: FnMut(&ast::ViewItem) -> bool {
let mut visit = EachViewItemData {
callback: f,
};
visit::walk_crate(&mut visit, self);
true
}
}
pub fn view_path_id(p: &ViewPath) -> NodeId {
match p.node {
ViewPathSimple(_, _, id) | ViewPathGlob(_, id)
| ViewPathList(_, _, id) => id
}
}
/// Returns true if the given struct def is tuple-like; i.e. that its fields
/// are unnamed.
pub fn struct_def_is_tuple_like(struct_def: &ast::StructDef) -> bool {
struct_def.ctor_id.is_some()
}
/// Returns true if the given pattern consists solely of an identifier
/// and false otherwise.
pub fn pat_is_ident(pat: P<ast::Pat>) -> bool {
match pat.node {
ast::PatIdent(..) => true,
_ => false,
}
}
// are two paths equal when compared unhygienically?
// since I'm using this to replace ==, it seems appropriate
// to compare the span, global, etc. fields as well.
pub fn path_name_eq(a : &ast::Path, b : &ast::Path) -> bool {
(a.span == b.span)
&& (a.global == b.global)
&& (segments_name_eq(a.segments.as_slice(), b.segments.as_slice()))
}
// are two arrays of segments equal when compared unhygienically?
pub fn segments_name_eq(a : &[ast::PathSegment], b : &[ast::PathSegment]) -> bool {
if a.len() != b.len() {
false
} else {
for (idx,seg) in a.iter().enumerate() {
if seg.identifier.name != b[idx].identifier.name
// FIXME #7743: ident -> name problems in lifetime comparison?
// can types contain idents?
|| seg.parameters != b[idx].parameters
{
return false;
}
}
true
}
}
/// Returns true if this literal is a string and false otherwise.
pub fn lit_is_str(lit: &Lit) -> bool {
match lit.node {
LitStr(..) => true,
_ => false,
}
}
/// Macro invocations are guaranteed not to occur after expansion is complete.
/// Extracting fields of a method requires a dynamic check to make sure that it's
/// not a macro invocation. This check is guaranteed to succeed, assuming
/// that the invocations are indeed gone.
pub trait PostExpansionMethod {
fn pe_ident(&self) -> ast::Ident;
fn pe_generics<'a>(&'a self) -> &'a ast::Generics;
fn pe_abi(&self) -> Abi;
fn pe_explicit_self<'a>(&'a self) -> &'a ast::ExplicitSelf;
fn pe_unsafety(&self) -> ast::Unsafety;
fn pe_fn_decl<'a>(&'a self) -> &'a ast::FnDecl;
fn pe_body<'a>(&'a self) -> &'a ast::Block;
fn pe_vis(&self) -> ast::Visibility;
}
macro_rules! mf_method{
($meth_name:ident, $field_ty:ty, $field_pat:pat, $result:expr) => {
fn $meth_name<'a>(&'a self) -> $field_ty {
match self.node {
$field_pat => $result,
MethMac(_) => {
panic!("expected an AST without macro invocations");
}
}
}
}
}
impl PostExpansionMethod for Method {
mf_method! { pe_ident,ast::Ident,MethDecl(ident,_,_,_,_,_,_,_),ident }
mf_method! {
pe_generics,&'a ast::Generics,
MethDecl(_,ref generics,_,_,_,_,_,_),generics
}
mf_method! { pe_abi,Abi,MethDecl(_,_,abi,_,_,_,_,_),abi }
mf_method! {
pe_explicit_self,&'a ast::ExplicitSelf,
MethDecl(_,_,_,ref explicit_self,_,_,_,_),explicit_self
}
mf_method! { pe_unsafety,ast::Unsafety,MethDecl(_,_,_,_,unsafety,_,_,_),unsafety }
mf_method! { pe_fn_decl,&'a ast::FnDecl,MethDecl(_,_,_,_,_,ref decl,_,_),&**decl }
mf_method! { pe_body,&'a ast::Block,MethDecl(_,_,_,_,_,_,ref body,_),&**body }
mf_method! { pe_vis,ast::Visibility,MethDecl(_,_,_,_,_,_,_,vis),vis }
}
#[cfg(test)]
mod test {
use ast::*;
use super::*;
fn ident_to_segment(id : &Ident) -> PathSegment {
PathSegment {identifier: id.clone(),
parameters: PathParameters::none()}
}
#[test] fn idents_name_eq_test() {
assert!(segments_name_eq(
[Ident{name:Name(3),ctxt:4}, Ident{name:Name(78),ctxt:82}]
.iter().map(ident_to_segment).collect::<Vec<PathSegment>>().as_slice(),
[Ident{name:Name(3),ctxt:104}, Ident{name:Name(78),ctxt:182}]
.iter().map(ident_to_segment).collect::<Vec<PathSegment>>().as_slice()));
assert!(!segments_name_eq(
[Ident{name:Name(3),ctxt:4}, Ident{name:Name(78),ctxt:82}]
.iter().map(ident_to_segment).collect::<Vec<PathSegment>>().as_slice(),
[Ident{name:Name(3),ctxt:104}, Ident{name:Name(77),ctxt:182}]
.iter().map(ident_to_segment).collect::<Vec<PathSegment>>().as_slice()));
}
}