1
Fork 0
rust/src/libsyntax/ext/deriving/iter_bytes.rs

257 lines
9.9 KiB
Rust
Raw Normal View History

// Copyright 2012-2013 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 core::prelude::*;
use ast;
use ast::{TraitTyParamBound, Ty, and, bind_by_ref, binop, deref, enum_def};
use ast::{enum_variant_kind, expr, expr_match, ident, impure_fn, item, item_};
use ast::{item_enum, item_impl, item_struct, Generics};
use ast::{m_imm, meta_item, method};
use ast::{named_field, or, pat, pat_ident, pat_wild, public, pure_fn};
use ast::{stmt, struct_def, struct_variant_kind};
use ast::{sty_by_ref, sty_region, tuple_variant_kind, ty_nil, TyParam};
use ast::{TyParamBound, ty_path, ty_rptr, unnamed_field, variant};
use ext::base::ext_ctxt;
use ext::build;
use ext::deriving::*;
use codemap::{span, spanned};
use ast_util;
use core::uint;
pub fn expand_deriving_iter_bytes(cx: @ext_ctxt,
span: span,
_mitem: @meta_item,
in_items: ~[@item])
-> ~[@item] {
expand_deriving(cx,
span,
in_items,
expand_deriving_iter_bytes_struct_def,
expand_deriving_iter_bytes_enum_def)
}
fn create_derived_iter_bytes_impl(cx: @ext_ctxt,
span: span,
type_ident: ident,
generics: &Generics,
method: @method)
-> @item {
let methods = [ method ];
let trait_path = [
cx.ident_of(~"core"),
cx.ident_of(~"to_bytes"),
cx.ident_of(~"IterBytes")
];
create_derived_impl(cx, span, type_ident, generics, methods, trait_path)
}
// Creates a method from the given set of statements conforming to the
// signature of the `iter_bytes` method.
fn create_iter_bytes_method(cx: @ext_ctxt,
span: span,
+statements: ~[@stmt])
-> @method {
// Create the `lsb0` parameter.
let bool_ident = cx.ident_of(~"bool");
let lsb0_arg_type = build::mk_simple_ty_path(cx, span, bool_ident);
let lsb0_ident = cx.ident_of(~"__lsb0");
let lsb0_arg = build::mk_arg(cx, span, lsb0_ident, lsb0_arg_type);
// Create the `f` parameter.
let core_ident = cx.ident_of(~"core");
let to_bytes_ident = cx.ident_of(~"to_bytes");
let cb_ident = cx.ident_of(~"Cb");
let core_to_bytes_cb_ident = ~[ core_ident, to_bytes_ident, cb_ident ];
let f_arg_type = build::mk_ty_path(cx, span, core_to_bytes_cb_ident);
let f_ident = cx.ident_of(~"__f");
let f_arg = build::mk_arg(cx, span, f_ident, f_arg_type);
// Create the type of the return value.
let output_type = @ast::Ty { id: cx.next_id(), node: ty_nil, span: span };
// Create the function declaration.
let inputs = ~[ lsb0_arg, f_arg ];
let fn_decl = build::mk_fn_decl(inputs, output_type);
// Create the body block.
let body_block = build::mk_block_(cx, span, statements);
// Create the method.
let self_ty = spanned { node: sty_region(None, m_imm), span: span };
let method_ident = cx.ident_of(~"iter_bytes");
@ast::method {
ident: method_ident,
attrs: ~[],
generics: ast_util::empty_generics(),
self_ty: self_ty,
purity: impure_fn,
decl: fn_decl,
body: body_block,
id: cx.next_id(),
span: span,
self_id: cx.next_id(),
vis: public
}
}
fn call_substructure_iter_bytes_method(cx: @ext_ctxt,
span: span,
self_field: @expr)
-> @stmt {
// Gather up the parameters we want to chain along.
let lsb0_ident = cx.ident_of(~"__lsb0");
let f_ident = cx.ident_of(~"__f");
let lsb0_expr = build::mk_path(cx, span, ~[ lsb0_ident ]);
let f_expr = build::mk_path(cx, span, ~[ f_ident ]);
// Call the substructure method.
let iter_bytes_ident = cx.ident_of(~"iter_bytes");
let self_method = build::mk_access_(cx,
span,
self_field,
iter_bytes_ident);
let self_call = build::mk_call_(cx,
span,
self_method,
~[ lsb0_expr, f_expr ]);
// Create a statement out of this expression.
build::mk_stmt(cx, span, self_call)
}
fn expand_deriving_iter_bytes_struct_def(cx: @ext_ctxt,
span: span,
struct_def: &struct_def,
type_ident: ident,
generics: &Generics)
-> @item {
// Create the method.
let method = expand_deriving_iter_bytes_struct_method(cx,
span,
struct_def);
// Create the implementation.
return create_derived_iter_bytes_impl(cx,
span,
type_ident,
generics,
method);
}
fn expand_deriving_iter_bytes_enum_def(cx: @ext_ctxt,
span: span,
enum_definition: &enum_def,
type_ident: ident,
generics: &Generics)
-> @item {
// Create the method.
let method = expand_deriving_iter_bytes_enum_method(cx,
span,
enum_definition);
// Create the implementation.
return create_derived_iter_bytes_impl(cx,
span,
type_ident,
generics,
method);
}
fn expand_deriving_iter_bytes_struct_method(cx: @ext_ctxt,
span: span,
struct_def: &struct_def)
-> @method {
let self_ident = cx.ident_of(~"self");
// Create the body of the method.
let mut statements = ~[];
for struct_def.fields.each |struct_field| {
match struct_field.node.kind {
named_field(ident, _, _) => {
// Create the accessor for this field.
let self_field = build::mk_access(cx,
span,
~[ self_ident ],
ident);
// Call the substructure method.
let stmt = call_substructure_iter_bytes_method(cx,
span,
self_field);
statements.push(stmt);
}
unnamed_field => {
cx.span_unimpl(span,
~"unnamed fields with `deriving_iter_bytes`");
}
}
}
// Create the method itself.
return create_iter_bytes_method(cx, span, statements);
}
fn expand_deriving_iter_bytes_enum_method(cx: @ext_ctxt,
span: span,
enum_definition: &enum_def)
-> @method {
// Create the arms of the match in the method body.
let arms = do enum_definition.variants.mapi |i, variant| {
// Create the matching pattern.
let pat = create_enum_variant_pattern(cx, span, variant, ~"__self");
// Determine the discriminant. We will feed this value to the byte
// iteration function.
let discriminant;
match variant.node.disr_expr {
Some(copy disr_expr) => discriminant = disr_expr,
None => discriminant = build::mk_uint(cx, span, i),
}
// Feed the discriminant to the byte iteration function.
let mut stmts = ~[];
let discrim_stmt = call_substructure_iter_bytes_method(cx,
span,
discriminant);
stmts.push(discrim_stmt);
// Feed each argument in this variant to the byte iteration function
// as well.
for uint::range(0, variant_arg_count(cx, span, variant)) |j| {
// Create the expression for this field.
let field_ident = cx.ident_of(~"__self" + j.to_str());
let field = build::mk_path(cx, span, ~[ field_ident ]);
// Call the substructure method.
let stmt = call_substructure_iter_bytes_method(cx, span, field);
stmts.push(stmt);
}
// Create the pattern body.
let match_body_block = build::mk_block_(cx, span, stmts);
// Create the arm.
ast::arm {
pats: ~[ pat ],
guard: None,
body: match_body_block,
}
};
// Create the method body.
let self_match_expr = expand_enum_or_struct_match(cx, span, arms);
let self_match_stmt = build::mk_stmt(cx, span, self_match_expr);
// Create the method.
create_iter_bytes_method(cx, span, ~[ self_match_stmt ])
}