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mirror of https://github.com/golang/go synced 2024-10-03 22:21:22 -06:00
go/usr/gri/pretty/printer.go
Robert Griesemer 82fbbdfc7d snapshot
- fixed expression and statement printing
- missing: declarations, comments

R=r
OCL=17207
CL=17207
2008-10-15 11:48:18 -07:00

431 lines
7.5 KiB
Go

// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package Printer
import Scanner "scanner"
import Node "node"
export type Printer struct {
level int; // true scope level
indent int; // indentation level
semi bool; // pending ";"
newl bool; // pending "\n"
}
func (P *Printer) String(s string) {
if P.semi && P.level > 0 { // no semicolons at level 0
print(";");
}
if P.newl {
print("\n");
for i := P.indent; i > 0; i-- {
print("\t");
}
}
print(s);
P.newl, P.semi = false, false;
}
func (P *Printer) Token(tok int) {
P.String(Scanner.TokenString(tok));
}
func (P *Printer) NewLine() { // explicit "\n"
print("\n");
P.semi, P.newl = false, true;
}
func (P *Printer) OpenScope(paren string) {
P.semi, P.newl = false, false;
P.String(paren);
P.level++;
P.indent++;
P.newl = true;
}
func (P *Printer) CloseScope(paren string) {
P.indent--;
P.semi = false;
P.String(paren);
P.level--;
P.semi, P.newl = false, true;
}
// ----------------------------------------------------------------------------
// Types
func (P *Printer) Expr(x *Node.Expr)
func (P *Printer) Type(t *Node.Type) {
switch t.tok {
case Scanner.IDENT:
P.Expr(t.expr);
case Scanner.LBRACK:
P.String("[");
if t.expr != nil {
P.Expr(t.expr);
}
P.String("] ");
P.Type(t.elt);
case Scanner.STRUCT:
P.String("struct");
if t.list != nil {
P.OpenScope(" {");
/*
for i := 0; i < x.fields.len(); i++ {
P.Print(x.fields.at(i));
P.newl, P.semi = true, true;
}
*/
P.CloseScope("}");
}
case Scanner.MAP:
P.String("[");
P.Type(t.key);
P.String("] ");
P.Type(t.elt);
case Scanner.CHAN:
switch t.mode {
case Node.FULL: P.String("chan ");
case Node.RECV: P.String("<-chan ");
case Node.SEND: P.String("chan <- ");
}
P.Type(t.elt);
case Scanner.INTERFACE:
P.String("interface");
if t.list != nil {
P.OpenScope(" {");
/*
for i := 0; i < x.methods.len(); i++ {
P.Print(x.methods.at(i));
P.newl, P.semi = true, true;
}
*/
P.CloseScope("}");
}
case Scanner.MUL:
P.String("*");
P.Type(t.elt);
case Scanner.LPAREN:
P.String("(");
//P.PrintList(x.params);
P.String(")");
/*
if x.result != nil {
P.String(" (");
P.PrintList(x.result);
P.String(")");
}
*/
default:
panic("UNREACHABLE");
}
}
// ----------------------------------------------------------------------------
// Expressions
func (P *Printer) Expr1(x *Node.Expr, prec1 int) {
if x == nil {
return; // empty expression list
}
switch x.tok {
case Scanner.IDENT, Scanner.INT, Scanner.STRING, Scanner.FLOAT:
P.String(x.s);
case Scanner.COMMA:
P.Expr1(x.x, 0);
P.String(", ");
P.Expr1(x.y, 0);
case Scanner.PERIOD:
P.Expr1(x.x, 8);
P.String(".");
P.Expr1(x.y, 8);
case Scanner.LBRACK:
P.Expr1(x.x, 8);
P.String("[");
P.Expr1(x.y, 0);
P.String("]");
case Scanner.LPAREN:
P.Expr1(x.x, 8);
P.String("(");
P.Expr1(x.y, 0);
P.String(")");
default:
if x.x == nil {
// unary expression
P.Token(x.tok);
P.Expr1(x.y, 7);
} else {
// binary expression: print ()'s if necessary
prec := Scanner.Precedence(x.tok);
if prec < prec1 {
print("(");
}
P.Expr1(x.x, prec);
P.String(" ");
P.Token(x.tok);
P.String(" ");
P.Expr1(x.y, prec);
if prec < prec1 {
print(")");
}
}
}
}
func (P *Printer) Expr(x *Node.Expr) {
P.Expr1(x, 0);
}
// ----------------------------------------------------------------------------
// Statements
func (P *Printer) Stat(s *Node.Stat)
func (P *Printer) StatementList(list *Node.List) {
for i, n := 0, list.len(); i < n; i++ {
P.Stat(list.at(i).(*Node.Stat));
P.newl = true;
}
}
func (P *Printer) Block(list *Node.List, indent bool) {
P.OpenScope("{");
if !indent {
P.indent--;
}
P.StatementList(list);
if !indent {
P.indent++;
}
P.CloseScope("}");
}
func (P *Printer) ControlClause(s *Node.Stat) {
if s.init != nil {
P.String(" ");
P.Stat(s.init);
P.semi = true;
P.String("");
}
if s.expr != nil {
P.String(" ");
P.Expr(s.expr);
P.semi = false;
}
if s.tok == Scanner.FOR && s.post != nil {
P.semi = true;
P.String(" ");
P.Stat(s.post);
P.semi = false;
}
P.String(" ");
}
func (P *Printer) Declaration(d *Node.Decl);
func (P *Printer) Stat(s *Node.Stat) {
if s == nil { // TODO remove this check
P.String("<nil stat>");
return;
}
switch s.tok {
case 0: // TODO use a real token const
P.Expr(s.expr);
P.semi = true;
case Scanner.CONST, Scanner.TYPE, Scanner.VAR:
P.Declaration(s.decl);
case Scanner.DEFINE, Scanner.ASSIGN, Scanner.ADD_ASSIGN,
Scanner.SUB_ASSIGN, Scanner.MUL_ASSIGN, Scanner.QUO_ASSIGN,
Scanner.REM_ASSIGN, Scanner.AND_ASSIGN, Scanner.OR_ASSIGN,
Scanner.XOR_ASSIGN, Scanner.SHL_ASSIGN, Scanner.SHR_ASSIGN:
P.Expr(s.lhs);
P.String(" ");
P.Token(s.tok);
P.String(" ");
P.Expr(s.expr);
P.semi = true;
case Scanner.INC, Scanner.DEC:
P.Expr(s.expr);
P.Token(s.tok);
P.semi = true;
case Scanner.LBRACE:
P.Block(s.block, true);
case Scanner.IF:
P.String("if");
P.ControlClause(s);
P.Block(s.block, true);
if s.post != nil {
P.newl = false;
P.String(" else ");
P.Stat(s.post);
}
case Scanner.FOR:
P.String("for");
P.ControlClause(s);
P.Block(s.block, true);
case Scanner.SWITCH, Scanner.SELECT:
P.Token(s.tok);
P.ControlClause(s);
P.Block(s.block, false);
case Scanner.CASE, Scanner.DEFAULT:
P.Token(s.tok);
if s.expr != nil {
P.String(" ");
P.Expr(s.expr);
}
P.String(":");
P.OpenScope("");
P.StatementList(s.block);
P.CloseScope("");
case Scanner.GO, Scanner.RETURN, Scanner.BREAK, Scanner.CONTINUE, Scanner.GOTO:
P.Token(s.tok);
P.String(" ");
P.Expr(s.expr);
P.semi = true;
default:
P.String("<stat>");
P.semi = true;
}
}
// ----------------------------------------------------------------------------
// Declarations
/*
func (P *Printer) DoFuncDecl(x *AST.FuncDecl) {
P.String("func ");
if x.typ.recv != nil {
P.String("(");
P.DoVarDeclList(x.typ.recv);
P.String(") ");
}
P.DoIdent(x.ident);
P.DoFunctionType(x.typ);
if x.body != nil {
P.String(" ");
P.DoBlock(x.body);
} else {
P.String(" ;");
}
P.NewLine();
P.NewLine();
}
func (P *Printer) DoMethodDecl(x *AST.MethodDecl) {
//P.DoIdent(x.ident);
//P.DoFunctionType(x.typ);
}
*/
func (P *Printer) Declaration(d *Node.Decl) {
if d.tok == Scanner.FUNC || d.ident == nil {
if d.exported {
P.String("export ");
}
P.Token(d.tok);
P.String(" ");
}
if d.ident == nil {
switch d.list.len() {
case 0:
P.String("()");
case 1:
P.Declaration(d.list.at(0).(*Node.Decl));
default:
P.OpenScope("(");
for i := 0; i < d.list.len(); i++ {
P.Declaration(d.list.at(i).(*Node.Decl));
P.newl, P.semi = true, true;
}
P.CloseScope(")");
}
} else {
P.Expr(d.ident);
if d.typ != nil {
P.String(" ");
P.Type(d.typ);
}
if d.val != nil {
P.String(" = ");
P.Expr(d.val);
}
if d.list != nil {
if d.tok != Scanner.FUNC {
panic("must be a func declaration");
}
P.String(" ");
P.Block(d.list, true);
}
}
// extra newline at the top level
if P.level == 0 {
P.NewLine();
}
P.newl = true;
}
// ----------------------------------------------------------------------------
// Program
func (P *Printer) Program(p *Node.Program) {
P.String("package ");
P.Expr(p.ident);
P.NewLine();
for i := 0; i < p.decls.len(); i++ {
P.Declaration(p.decls.at(i));
}
P.newl = true;
P.String("");
}