From bf0caa6f327d84025d9891bdbd6784eb6075fa9f Mon Sep 17 00:00:00 2001
From: ceriel <none@none>
Date: Wed, 27 Nov 1991 13:40:52 +0000
Subject: [PATCH] Changed error-messages mechanism

---
 lang/m2/comp/BigPars     |  6 +++---
 lang/m2/comp/LLlex.c     |  5 +++++
 lang/m2/comp/LLlex.h     |  3 +++
 lang/m2/comp/LLmessage.c |  1 +
 lang/m2/comp/SmallPars   |  5 +++--
 lang/m2/comp/error.c     | 30 ++++++------------------------
 6 files changed, 21 insertions(+), 29 deletions(-)

diff --git a/lang/m2/comp/BigPars b/lang/m2/comp/BigPars
index 5bc986017..66a624018 100644
--- a/lang/m2/comp/BigPars
+++ b/lang/m2/comp/BigPars
@@ -1,8 +1,8 @@
 !File: errout.h
 #define	ERROUT		STDERR	/* file pointer for writing messages	*/
-#define	MAXERR_LINE	100	/* maximum number of error messages given
-					on the same input line.		*/
-
+#define ERR_SHADOW      5       /* a syntax error overshadows error messages
+                                        until ERR_SHADOW symbols have been
+                                        accepted without syntax error */
 
 !File: idfsize.h
 #define	IDFSIZE	128	/* maximum significant length of an identifier	*/
diff --git a/lang/m2/comp/LLlex.c b/lang/m2/comp/LLlex.c
index e047bd776..15c27ff40 100644
--- a/lang/m2/comp/LLlex.c
+++ b/lang/m2/comp/LLlex.c
@@ -28,6 +28,7 @@
 #include	"def.h"
 #include	"type.h"
 #include	"warning.h"
+#include	"errout.h"
 
 extern char *getwdir();
 
@@ -40,6 +41,9 @@ int		ForeignFlag;
 extern int	cntlines;
 #endif
 
+int	token_nmb = 0;
+int	tk_nmb_at_last_syn_err = -ERR_SHADOW;
+
 extern char	options[];
 extern int	flt_status;
 
@@ -266,6 +270,7 @@ LLlex()
 		return tk->tk_symb;
 	}
 
+	token_nmb++;
 again:
 	ch = getch();
 	tk->tk_lineno = LineNumber;
diff --git a/lang/m2/comp/LLlex.h b/lang/m2/comp/LLlex.h
index 1f379227f..a91a76de9 100644
--- a/lang/m2/comp/LLlex.h
+++ b/lang/m2/comp/LLlex.h
@@ -65,3 +65,6 @@ extern struct type *toktype;
 
 #define DOT	dot.tk_symb
 #define ASIDE	aside.tk_symb
+
+extern int	token_nmb;
+extern int	tk_nmb_at_last_syn_err;
diff --git a/lang/m2/comp/LLmessage.c b/lang/m2/comp/LLmessage.c
index c45403f63..232cc98b4 100644
--- a/lang/m2/comp/LLmessage.c
+++ b/lang/m2/comp/LLmessage.c
@@ -65,5 +65,6 @@ LLmessage(tk)
 		error("garbage at end of program");
 	}
 	else	error("%s deleted", symbol2str(dot.tk_symb));
+	tk_nmb_at_last_syn_err = token_nmb;
 }
 
diff --git a/lang/m2/comp/SmallPars b/lang/m2/comp/SmallPars
index fc7741399..13f987082 100644
--- a/lang/m2/comp/SmallPars
+++ b/lang/m2/comp/SmallPars
@@ -1,7 +1,8 @@
 !File: errout.h
 #define	ERROUT		STDERR	/* file pointer for writing messages	*/
-#define	MAXERR_LINE	100	/* maximum number of error messages given
-					on the same input line.		*/
+#define ERR_SHADOW      5       /* a syntax error overshadows error messages
+                                        until ERR_SHADOW symbols have been
+                                        accepted without syntax error */
 
 
 !File: idfsize.h
diff --git a/lang/m2/comp/error.c b/lang/m2/comp/error.c
index e3f4041fe..da84872b4 100644
--- a/lang/m2/comp/error.c
+++ b/lang/m2/comp/error.c
@@ -195,14 +195,17 @@ _error(class, node, ap)
 	/*	_error attempts to limit the number of error messages
 		for a given line to MAXERR_LINE.
 	*/
-	static unsigned int last_ln = 0;
 	unsigned int ln = 0;
-	static char * last_fn = 0;
-	static int e_seen = 0;
 	register char *remark = 0;
 	int warn_class;
 	char *fmt;
 	
+	/* check visibility of message */
+	if (class == ERROR || class == WARNING) {
+		if (token_nmb < tk_nmb_at_last_syn_err + ERR_SHADOW)
+			/* warning or error message overshadowed */
+			return;
+	}
 	/*	Since name and number are gathered from different places
 		depending on the class, we first collect the relevant
 		values and then decide what to print.
@@ -271,27 +274,6 @@ _error(class, node, ap)
 	}
 
 	fmt  = va_arg(ap, char *);	
-#ifdef DEBUG
-	if (class != VDEBUG) {
-#endif
-	if (FileName == last_fn && ln == last_ln)	{
-		/* we've seen this place before */
-		e_seen++;
-		if (e_seen == MAXERR_LINE) fmt = "etc ...";
-		else
-		if (e_seen > MAXERR_LINE)
-			/* and too often, I'd say ! */
-			return;
-	}
-	else	{
-		/* brand new place */
-		last_ln = ln;
-		last_fn = FileName;
-		e_seen = 0;
-	}
-#ifdef DEBUG
-	}
-#endif DEBUG
 	
 	if (FileName) fprint(ERROUT, "\"%s\", line %u: ", FileName, ln);