mirror of
https://github.com/golang/go
synced 2024-10-04 02:21:21 -06:00
522 lines
12 KiB
Go
522 lines
12 KiB
Go
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package ast
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import (
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"vector";
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"token";
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"scanner";
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)
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type (
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Block struct;
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Expr interface;
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Decl interface;
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)
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// ----------------------------------------------------------------------------
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// Support
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func assert(pred bool) {
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if !pred {
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panic("assertion failed");
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}
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}
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// ----------------------------------------------------------------------------
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// Expressions
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const /* channel mode */ (
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FULL = iota;
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SEND;
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RECV;
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)
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type (
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ExprVisitor interface;
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Signature struct;
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Expr interface {
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Loc() scanner.Location;
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Visit(v ExprVisitor);
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};
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BadExpr struct {
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Loc_ scanner.Location;
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};
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Ident struct {
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Loc_ scanner.Location;
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Str string;
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};
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BinaryExpr struct {
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Loc_ scanner.Location;
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Tok int;
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X, Y Expr;
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};
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UnaryExpr struct {
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Loc_ scanner.Location;
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Tok int;
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X Expr;
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};
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// TODO this should probably just be a list instead
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ConcatExpr struct {
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X, Y Expr;
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};
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BasicLit struct {
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Loc_ scanner.Location;
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Tok int;
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Val []byte;
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};
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FunctionLit struct {
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Loc_ scanner.Location; // location of "func"
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Typ *Signature;
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Body *Block;
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};
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Group struct {
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Loc_ scanner.Location; // location of "("
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X Expr;
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};
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Selector struct {
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Loc_ scanner.Location; // location of "."
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X Expr;
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Sel *Ident;
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};
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TypeGuard struct {
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Loc_ scanner.Location; // location of "."
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X Expr;
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Typ Expr;
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};
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Index struct {
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Loc_ scanner.Location; // location of "["
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X, I Expr;
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};
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Call struct {
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Loc_ scanner.Location; // location of "(" or "{"
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Tok int;
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F, Args Expr
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};
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// Type literals are treated like expressions.
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Ellipsis struct { // neither a type nor an expression
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Loc_ scanner.Location;
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};
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TypeType struct { // for type switches
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Loc_ scanner.Location; // location of "type"
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};
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ArrayType struct {
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Loc_ scanner.Location; // location of "["
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Len Expr;
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Elt Expr;
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};
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Field struct {
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Idents []*Ident;
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Typ Expr;
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Tag Expr; // nil = no tag
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};
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StructType struct {
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Loc_ scanner.Location; // location of "struct"
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Fields []*Field;
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End scanner.Location; // location of "}"
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};
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PointerType struct {
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Loc_ scanner.Location; // location of "*"
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Base Expr;
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};
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Signature struct {
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Params []*Field;
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Result []*Field;
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};
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FunctionType struct {
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Loc_ scanner.Location; // location of "func"
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Sig *Signature;
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};
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InterfaceType struct {
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Loc_ scanner.Location; // location of "interface"
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Methods []*Field;
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End scanner.Location; // location of "}", End == 0 if forward declaration
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};
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SliceType struct {
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Loc_ scanner.Location; // location of "["
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};
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MapType struct {
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Loc_ scanner.Location; // location of "map"
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Key Expr;
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Val Expr;
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};
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ChannelType struct {
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Loc_ scanner.Location; // location of "chan" or "<-"
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Mode int;
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Val Expr;
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};
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)
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type ExprVisitor interface {
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DoBadExpr(x *BadExpr);
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DoIdent(x *Ident);
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DoBinaryExpr(x *BinaryExpr);
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DoUnaryExpr(x *UnaryExpr);
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DoConcatExpr(x *ConcatExpr);
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DoBasicLit(x *BasicLit);
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DoFunctionLit(x *FunctionLit);
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DoGroup(x *Group);
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DoSelector(x *Selector);
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DoTypeGuard(x *TypeGuard);
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DoIndex(x *Index);
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DoCall(x *Call);
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DoEllipsis(x *Ellipsis);
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DoTypeType(x *TypeType);
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DoArrayType(x *ArrayType);
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DoStructType(x *StructType);
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DoPointerType(x *PointerType);
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DoFunctionType(x *FunctionType);
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DoInterfaceType(x *InterfaceType);
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DoSliceType(x *SliceType);
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DoMapType(x *MapType);
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DoChannelType(x *ChannelType);
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}
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// TODO replace these with an embedded field
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func (x *BadExpr) Loc() scanner.Location { return x.Loc_; }
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func (x *Ident) Loc() scanner.Location { return x.Loc_; }
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func (x *BinaryExpr) Loc() scanner.Location { return x.Loc_; }
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func (x *UnaryExpr) Loc() scanner.Location { return x.Loc_; }
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func (x *ConcatExpr) Loc() scanner.Location { return x.X.Loc(); }
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func (x *BasicLit) Loc() scanner.Location { return x.Loc_; }
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func (x *FunctionLit) Loc() scanner.Location { return x.Loc_; }
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func (x *Group) Loc() scanner.Location { return x.Loc_; }
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func (x *Selector) Loc() scanner.Location { return x.Loc_; }
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func (x *TypeGuard) Loc() scanner.Location { return x.Loc_; }
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func (x *Index) Loc() scanner.Location { return x.Loc_; }
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func (x *Call) Loc() scanner.Location { return x.Loc_; }
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func (x *Ellipsis) Loc() scanner.Location { return x.Loc_; }
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func (x *TypeType) Loc() scanner.Location { return x.Loc_; }
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func (x *ArrayType) Loc() scanner.Location { return x.Loc_; }
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func (x *StructType) Loc() scanner.Location { return x.Loc_; }
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func (x *PointerType) Loc() scanner.Location { return x.Loc_; }
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func (x *FunctionType) Loc() scanner.Location { return x.Loc_; }
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func (x *InterfaceType) Loc() scanner.Location { return x.Loc_; }
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func (x *SliceType) Loc() scanner.Location { return x.Loc_; }
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func (x *MapType) Loc() scanner.Location { return x.Loc_; }
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func (x *ChannelType) Loc() scanner.Location { return x.Loc_; }
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func (x *BadExpr) Visit(v ExprVisitor) { v.DoBadExpr(x); }
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func (x *Ident) Visit(v ExprVisitor) { v.DoIdent(x); }
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func (x *BinaryExpr) Visit(v ExprVisitor) { v.DoBinaryExpr(x); }
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func (x *UnaryExpr) Visit(v ExprVisitor) { v.DoUnaryExpr(x); }
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func (x *ConcatExpr) Visit(v ExprVisitor) { v.DoConcatExpr(x); }
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func (x *BasicLit) Visit(v ExprVisitor) { v.DoBasicLit(x); }
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func (x *FunctionLit) Visit(v ExprVisitor) { v.DoFunctionLit(x); }
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func (x *Group) Visit(v ExprVisitor) { v.DoGroup(x); }
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func (x *Selector) Visit(v ExprVisitor) { v.DoSelector(x); }
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func (x *TypeGuard) Visit(v ExprVisitor) { v.DoTypeGuard(x); }
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func (x *Index) Visit(v ExprVisitor) { v.DoIndex(x); }
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func (x *Call) Visit(v ExprVisitor) { v.DoCall(x); }
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func (x *Ellipsis) Visit(v ExprVisitor) { v.DoEllipsis(x); }
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func (x *TypeType) Visit(v ExprVisitor) { v.DoTypeType(x); }
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func (x *ArrayType) Visit(v ExprVisitor) { v.DoArrayType(x); }
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func (x *StructType) Visit(v ExprVisitor) { v.DoStructType(x); }
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func (x *PointerType) Visit(v ExprVisitor) { v.DoPointerType(x); }
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func (x *FunctionType) Visit(v ExprVisitor) { v.DoFunctionType(x); }
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func (x *InterfaceType) Visit(v ExprVisitor) { v.DoInterfaceType(x); }
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func (x *SliceType) Visit(v ExprVisitor) { v.DoSliceType(x); }
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func (x *MapType) Visit(v ExprVisitor) { v.DoMapType(x); }
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func (x *ChannelType) Visit(v ExprVisitor) { v.DoChannelType(x); }
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// Length of a comma-separated expression list.
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func ExprLen(x Expr) int {
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if x == nil {
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return 0;
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}
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n := 1;
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for {
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if p, ok := x.(*BinaryExpr); ok && p.Tok == token.COMMA {
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n++;
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x = p.Y;
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} else {
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break;
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}
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}
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return n;
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}
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func ExprAt(x Expr, i int) Expr {
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for j := 0; j < i; j++ {
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assert(x.(*BinaryExpr).Tok == token.COMMA);
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x = x.(*BinaryExpr).Y;
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}
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if t, is_binary := x.(*BinaryExpr); is_binary && t.Tok == token.COMMA {
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x = t.X;
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}
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return x;
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}
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// ----------------------------------------------------------------------------
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// Blocks
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//
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// Syntactic constructs of the form:
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//
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// "{" StatementList "}"
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// ":" StatementList
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type Block struct {
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Loc scanner.Location;
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Tok int;
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List *vector.Vector;
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End scanner.Location; // location of closing "}" if present
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}
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func NewBlock(loc scanner.Location, tok int) *Block {
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assert(tok == token.LBRACE || tok == token.COLON);
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var end scanner.Location;
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return &Block{loc, tok, vector.New(0), end};
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}
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// ----------------------------------------------------------------------------
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// Statements
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type (
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StatVisitor interface;
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Stat interface {
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Visit(v StatVisitor);
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};
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BadStat struct {
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Loc scanner.Location;
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};
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LabelDecl struct {
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Loc scanner.Location; // location of ":"
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Label *Ident;
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};
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DeclarationStat struct {
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Decl Decl;
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};
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ExpressionStat struct {
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Loc scanner.Location; // location of Tok
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Tok int; // INC, DEC, RETURN, GO, DEFER
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Expr Expr;
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};
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CompositeStat struct {
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Body *Block;
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};
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IfStat struct {
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Loc scanner.Location; // location of "if"
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Init Stat;
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Cond Expr;
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Body *Block;
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Else Stat;
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};
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ForStat struct {
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Loc scanner.Location; // location of "for"
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Init Stat;
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Cond Expr;
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Post Stat;
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Body *Block;
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};
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CaseClause struct {
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Loc scanner.Location; // position for "case" or "default"
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Expr Expr; // nil means default case
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Body *Block;
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};
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SwitchStat struct {
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Loc scanner.Location; // location of "switch"
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Init Stat;
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Tag Expr;
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Body *Block;
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};
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SelectStat struct {
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Loc scanner.Location; // location of "select"
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Body *Block;
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};
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ControlFlowStat struct {
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Loc scanner.Location; // location of Tok
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Tok int; // BREAK, CONTINUE, GOTO, FALLTHROUGH
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Label *Ident; // if any, or nil
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};
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EmptyStat struct {
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Loc scanner.Location; // location of ";"
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};
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)
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type StatVisitor interface {
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DoBadStat(s *BadStat);
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DoLabelDecl(s *LabelDecl);
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DoDeclarationStat(s *DeclarationStat);
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DoExpressionStat(s *ExpressionStat);
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DoCompositeStat(s *CompositeStat);
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DoIfStat(s *IfStat);
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DoForStat(s *ForStat);
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DoCaseClause(s *CaseClause);
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DoSwitchStat(s *SwitchStat);
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DoSelectStat(s *SelectStat);
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DoControlFlowStat(s *ControlFlowStat);
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DoEmptyStat(s *EmptyStat);
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}
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func (s *BadStat) Visit(v StatVisitor) { v.DoBadStat(s); }
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func (s *LabelDecl) Visit(v StatVisitor) { v.DoLabelDecl(s); }
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func (s *DeclarationStat) Visit(v StatVisitor) { v.DoDeclarationStat(s); }
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func (s *ExpressionStat) Visit(v StatVisitor) { v.DoExpressionStat(s); }
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func (s *CompositeStat) Visit(v StatVisitor) { v.DoCompositeStat(s); }
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func (s *IfStat) Visit(v StatVisitor) { v.DoIfStat(s); }
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func (s *ForStat) Visit(v StatVisitor) { v.DoForStat(s); }
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func (s *CaseClause) Visit(v StatVisitor) { v.DoCaseClause(s); }
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func (s *SwitchStat) Visit(v StatVisitor) { v.DoSwitchStat(s); }
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func (s *SelectStat) Visit(v StatVisitor) { v.DoSelectStat(s); }
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func (s *ControlFlowStat) Visit(v StatVisitor) { v.DoControlFlowStat(s); }
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func (s *EmptyStat) Visit(v StatVisitor) { v.DoEmptyStat(s); }
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// ----------------------------------------------------------------------------
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// Declarations
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type (
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DeclVisitor interface;
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Decl interface {
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Visit(v DeclVisitor);
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};
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BadDecl struct {
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Loc scanner.Location;
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};
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ImportDecl struct {
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Loc scanner.Location; // if > 0: position of "import"
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Ident *Ident;
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Path Expr;
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};
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ConstDecl struct {
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Loc scanner.Location; // if > 0: position of "const"
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Idents []*Ident;
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Typ Expr;
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Vals Expr;
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};
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TypeDecl struct {
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Loc scanner.Location; // if > 0: position of "type"
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Ident *Ident;
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Typ Expr;
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};
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VarDecl struct {
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Loc scanner.Location; // if > 0: position of "var"
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Idents []*Ident;
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Typ Expr;
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Vals Expr;
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};
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FuncDecl struct {
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Loc scanner.Location; // location of "func"
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Recv *Field;
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Ident *Ident;
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Sig *Signature;
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Body *Block;
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};
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DeclList struct {
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Loc scanner.Location; // location of Tok
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Tok int;
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List []Decl;
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End scanner.Location;
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};
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)
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type DeclVisitor interface {
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DoBadDecl(d *BadDecl);
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DoImportDecl(d *ImportDecl);
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DoConstDecl(d *ConstDecl);
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DoTypeDecl(d *TypeDecl);
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DoVarDecl(d *VarDecl);
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DoFuncDecl(d *FuncDecl);
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DoDeclList(d *DeclList);
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}
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func (d *BadDecl) Visit(v DeclVisitor) { v.DoBadDecl(d); }
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func (d *ImportDecl) Visit(v DeclVisitor) { v.DoImportDecl(d); }
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func (d *ConstDecl) Visit(v DeclVisitor) { v.DoConstDecl(d); }
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func (d *TypeDecl) Visit(v DeclVisitor) { v.DoTypeDecl(d); }
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func (d *VarDecl) Visit(v DeclVisitor) { v.DoVarDecl(d); }
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func (d *FuncDecl) Visit(v DeclVisitor) { v.DoFuncDecl(d); }
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func (d *DeclList) Visit(v DeclVisitor) { v.DoDeclList(d); }
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// ----------------------------------------------------------------------------
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// Program
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type Comment struct {
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Loc scanner.Location;
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Text []byte;
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}
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type Program struct {
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Loc scanner.Location; // tok is token.PACKAGE
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Ident *Ident;
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Decls []Decl;
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Comments []*Comment;
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}
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func NewProgram(loc scanner.Location) *Program {
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p := new(Program);
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p.Loc = loc;
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return p;
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}
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