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2019-11-08 03:27:32 -06:00
Compiler Generator Coco/R,
Copyright (c) 1990, 2004 Hanspeter Moessenboeck, University of Linz
extended by M. Loeberbauer & A. Woess, Univ. of Linz
with improvements by Pat Terry, Rhodes University
This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 2, or (at your option) any
later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
As an exception, it is allowed to write an extension of Coco/R that is
used as a plugin in non-free software.
If not otherwise stated, any source code generated by Coco/R (other than
Coco/R itself) does not fall under the GNU General Public License.
using System;
public class Parser {
const bool T = true;
const bool x = false;
const int minErrDist = 2;
public Scanner scanner;
public Errors errors;
public Token t; // last recognized token
public Token la; // lookahead token
int errDist = minErrDist;
public Parser(Scanner scanner) {
this.scanner = scanner;
errors = new Errors();
void SynErr (int n) {
if (errDist >= minErrDist) errors.SynErr(la.line, la.col, n);
errDist = 0;
public void SemErr (string msg) {
if (errDist >= minErrDist) errors.SemErr(t.line, t.col, msg);
errDist = 0;
void Get () {
for (;;) {
t = la;
la = scanner.Scan();
if (la.kind <= maxT) { ++errDist; break; }
la = t;
void Expect (int n) {
if (la.kind==n) Get(); else { SynErr(n); }
bool StartOf (int s) {
return set[s, la.kind];
void ExpectWeak (int n, int follow) {
if (la.kind == n) Get();
else {
while (!StartOf(follow)) Get();
bool WeakSeparator(int n, int syFol, int repFol) {
int kind = la.kind;
if (kind == n) {Get(); return true;}
else if (StartOf(repFol)) {return false;}
else {
while (!(set[syFol, kind] || set[repFol, kind] || set[0, kind])) {
kind = la.kind;
return StartOf(syFol);
public void Parse() {
la = new Token();
la.val = "";
static readonly bool[,] set = {
} // end Parser
public class Errors {
public int count = 0; // number of errors detected
public System.IO.TextWriter errorStream = Console.Out; // error messages go to this stream
public string errMsgFormat = "-- line {0} col {1}: {2}"; // 0=line, 1=column, 2=text
public virtual void SynErr (int line, int col, int n) {
string s;
switch (n) {
default: s = "error " + n; break;
errorStream.WriteLine(errMsgFormat, line, col, s);
public virtual void SemErr (int line, int col, string s) {
errorStream.WriteLine(errMsgFormat, line, col, s);
public virtual void SemErr (string s) {
public virtual void Warning (int line, int col, string s) {
errorStream.WriteLine(errMsgFormat, line, col, s);
public virtual void Warning(string s) {
} // Errors
public class FatalError: Exception {
public FatalError(string m): base(m) {}