257 lines
9.9 KiB
Rust
257 lines
9.9 KiB
Rust
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// Copyright 2012-2013 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use core::prelude::*;
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use ast;
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use ast::{TraitTyParamBound, Ty, and, bind_by_ref, binop, deref, enum_def};
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use ast::{enum_variant_kind, expr, expr_match, ident, impure_fn, item, item_};
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use ast::{item_enum, item_impl, item_struct, Generics};
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use ast::{m_imm, meta_item, method};
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use ast::{named_field, or, pat, pat_ident, pat_wild, public, pure_fn};
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use ast::{stmt, struct_def, struct_variant_kind};
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use ast::{sty_by_ref, sty_region, tuple_variant_kind, ty_nil, TyParam};
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use ast::{TyParamBound, ty_path, ty_rptr, unnamed_field, variant};
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use ext::base::ext_ctxt;
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use ext::build;
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use ext::deriving::*;
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use codemap::{span, spanned};
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use ast_util;
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use core::uint;
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pub fn expand_deriving_iter_bytes(cx: @ext_ctxt,
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span: span,
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_mitem: @meta_item,
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in_items: ~[@item])
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-> ~[@item] {
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expand_deriving(cx,
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span,
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in_items,
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expand_deriving_iter_bytes_struct_def,
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expand_deriving_iter_bytes_enum_def)
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}
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fn create_derived_iter_bytes_impl(cx: @ext_ctxt,
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span: span,
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type_ident: ident,
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generics: &Generics,
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method: @method)
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-> @item {
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let methods = [ method ];
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let trait_path = [
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cx.ident_of(~"core"),
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cx.ident_of(~"to_bytes"),
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cx.ident_of(~"IterBytes")
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];
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create_derived_impl(cx, span, type_ident, generics, methods, trait_path)
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}
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// Creates a method from the given set of statements conforming to the
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// signature of the `iter_bytes` method.
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fn create_iter_bytes_method(cx: @ext_ctxt,
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span: span,
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+statements: ~[@stmt])
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-> @method {
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// Create the `lsb0` parameter.
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let bool_ident = cx.ident_of(~"bool");
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let lsb0_arg_type = build::mk_simple_ty_path(cx, span, bool_ident);
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let lsb0_ident = cx.ident_of(~"__lsb0");
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let lsb0_arg = build::mk_arg(cx, span, lsb0_ident, lsb0_arg_type);
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// Create the `f` parameter.
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let core_ident = cx.ident_of(~"core");
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let to_bytes_ident = cx.ident_of(~"to_bytes");
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let cb_ident = cx.ident_of(~"Cb");
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let core_to_bytes_cb_ident = ~[ core_ident, to_bytes_ident, cb_ident ];
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let f_arg_type = build::mk_ty_path(cx, span, core_to_bytes_cb_ident);
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let f_ident = cx.ident_of(~"__f");
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let f_arg = build::mk_arg(cx, span, f_ident, f_arg_type);
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// Create the type of the return value.
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let output_type = @ast::Ty { id: cx.next_id(), node: ty_nil, span: span };
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// Create the function declaration.
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let inputs = ~[ lsb0_arg, f_arg ];
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let fn_decl = build::mk_fn_decl(inputs, output_type);
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// Create the body block.
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let body_block = build::mk_block_(cx, span, statements);
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// Create the method.
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let self_ty = spanned { node: sty_region(None, m_imm), span: span };
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let method_ident = cx.ident_of(~"iter_bytes");
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@ast::method {
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ident: method_ident,
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attrs: ~[],
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generics: ast_util::empty_generics(),
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self_ty: self_ty,
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purity: impure_fn,
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decl: fn_decl,
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body: body_block,
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id: cx.next_id(),
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span: span,
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self_id: cx.next_id(),
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vis: public
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}
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}
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fn call_substructure_iter_bytes_method(cx: @ext_ctxt,
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span: span,
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self_field: @expr)
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-> @stmt {
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// Gather up the parameters we want to chain along.
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let lsb0_ident = cx.ident_of(~"__lsb0");
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let f_ident = cx.ident_of(~"__f");
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let lsb0_expr = build::mk_path(cx, span, ~[ lsb0_ident ]);
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let f_expr = build::mk_path(cx, span, ~[ f_ident ]);
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// Call the substructure method.
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let iter_bytes_ident = cx.ident_of(~"iter_bytes");
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let self_method = build::mk_access_(cx,
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span,
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self_field,
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iter_bytes_ident);
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let self_call = build::mk_call_(cx,
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span,
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self_method,
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~[ lsb0_expr, f_expr ]);
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// Create a statement out of this expression.
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build::mk_stmt(cx, span, self_call)
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}
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fn expand_deriving_iter_bytes_struct_def(cx: @ext_ctxt,
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span: span,
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struct_def: &struct_def,
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type_ident: ident,
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generics: &Generics)
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-> @item {
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// Create the method.
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let method = expand_deriving_iter_bytes_struct_method(cx,
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span,
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struct_def);
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// Create the implementation.
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return create_derived_iter_bytes_impl(cx,
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span,
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type_ident,
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generics,
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method);
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}
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fn expand_deriving_iter_bytes_enum_def(cx: @ext_ctxt,
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span: span,
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enum_definition: &enum_def,
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type_ident: ident,
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generics: &Generics)
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-> @item {
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// Create the method.
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let method = expand_deriving_iter_bytes_enum_method(cx,
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span,
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enum_definition);
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// Create the implementation.
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return create_derived_iter_bytes_impl(cx,
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span,
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type_ident,
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generics,
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method);
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}
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fn expand_deriving_iter_bytes_struct_method(cx: @ext_ctxt,
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span: span,
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struct_def: &struct_def)
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-> @method {
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let self_ident = cx.ident_of(~"self");
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// Create the body of the method.
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let mut statements = ~[];
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for struct_def.fields.each |struct_field| {
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match struct_field.node.kind {
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named_field(ident, _, _) => {
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// Create the accessor for this field.
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let self_field = build::mk_access(cx,
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span,
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~[ self_ident ],
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ident);
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// Call the substructure method.
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let stmt = call_substructure_iter_bytes_method(cx,
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span,
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self_field);
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statements.push(stmt);
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}
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unnamed_field => {
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cx.span_unimpl(span,
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~"unnamed fields with `deriving_iter_bytes`");
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}
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}
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}
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// Create the method itself.
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return create_iter_bytes_method(cx, span, statements);
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}
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fn expand_deriving_iter_bytes_enum_method(cx: @ext_ctxt,
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span: span,
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enum_definition: &enum_def)
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-> @method {
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// Create the arms of the match in the method body.
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let arms = do enum_definition.variants.mapi |i, variant| {
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// Create the matching pattern.
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let pat = create_enum_variant_pattern(cx, span, variant, ~"__self");
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// Determine the discriminant. We will feed this value to the byte
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// iteration function.
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let discriminant;
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match variant.node.disr_expr {
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Some(copy disr_expr) => discriminant = disr_expr,
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None => discriminant = build::mk_uint(cx, span, i),
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}
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// Feed the discriminant to the byte iteration function.
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let mut stmts = ~[];
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let discrim_stmt = call_substructure_iter_bytes_method(cx,
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span,
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discriminant);
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stmts.push(discrim_stmt);
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// Feed each argument in this variant to the byte iteration function
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// as well.
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for uint::range(0, variant_arg_count(cx, span, variant)) |j| {
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// Create the expression for this field.
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let field_ident = cx.ident_of(~"__self" + j.to_str());
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let field = build::mk_path(cx, span, ~[ field_ident ]);
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// Call the substructure method.
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let stmt = call_substructure_iter_bytes_method(cx, span, field);
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stmts.push(stmt);
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}
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// Create the pattern body.
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let match_body_block = build::mk_block_(cx, span, stmts);
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// Create the arm.
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ast::arm {
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pats: ~[ pat ],
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guard: None,
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body: match_body_block,
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}
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};
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// Create the method body.
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let self_match_expr = expand_enum_or_struct_match(cx, span, arms);
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let self_match_stmt = build::mk_stmt(cx, span, self_match_expr);
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// Create the method.
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create_iter_bytes_method(cx, span, ~[ self_match_stmt ])
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}
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