# HG changeset patch
# User Mychaela Falconia <falcon@freecalypso.org>
# Date 1648959428 0
# Node ID 3e398f9c31a0383096d490b5dd222752ae1aea27
# Parent  0d681423810967e843be678c818222507dd04d93
fc-imy2pwt: overhaul melody error handling, report position

diff -r 0d6814238109 -r 3e398f9c31a0 ringtools/imy/convert.c
--- a/ringtools/imy/convert.c	Sun Apr 03 04:00:09 2022 +0000
+++ b/ringtools/imy/convert.c	Sun Apr 03 04:17:08 2022 +0000
@@ -19,14 +19,23 @@
 				   "g", "gs", "a", "as", "b"};
 
 static void
-process_octave_cmd(octchar)
+melody_error(cp, msg)
+	char *cp, *msg;
 {
-	if (!isdigit(octchar)) {
-		fprintf(stderr,
-		"melody error: '*' octave prefix not followed by digit\n");
-		exit(1);
-	}
-	cur_octave = octchar - '0';
+	unsigned pos;
+
+	pos = cp - melody_str_buf;
+	fprintf(stderr, "melody error at offset %u: %s\n", pos, msg);
+	exit(1);
+}
+
+static void
+process_octave_cmd(cp)
+	char *cp;
+{
+	if (!isdigit(cp[1]))
+		melody_error(cp, "'*' octave prefix not followed by digit");
+	cur_octave = cp[1] - '0';
 }
 
 static int
@@ -58,31 +67,22 @@
 		note = 11;
 		break;
 	default:
-		fprintf(stderr,
-		"melody error: note letter expected after '&' or '#'\n");
-		exit(1);
+		melody_error(str, "note letter expected after '&' or '#'");
 	}
 	switch (type) {
 	case 1:
-		if (note == 0 || note == 5) {
-			fprintf(stderr, "melody error: invalid flat note\n");
-			exit(1);
-		}
+		if (note == 0 || note == 5)
+			melody_error(str, "invalid flat note");
 		note--;
 		break;
 	case 2:
-		if (note == 4 || note == 11) {
-			fprintf(stderr, "melody error: invalid sharp note\n");
-			exit(1);
-		}
+		if (note == 4 || note == 11)
+			melody_error(str, "invalid sharp note");
 		note++;
 		break;
 	}
-	if (str[1] < '0' || str[1] > '5') {
-		fprintf(stderr,
-			"melody error: missing expected note duration digit\n");
-		exit(1);
-	}
+	if (str[1] < '0' || str[1] > '5')
+		melody_error(str, "missing expected note duration digit");
 	dur_basic = str[1] - '0';
 	switch (str[2]) {
 	case '.':
@@ -112,11 +112,8 @@
 {
 	int dur_basic, dur_mod;
 
-	if (str[1] < '0' || str[1] > '5') {
-		fprintf(stderr,
-			"melody error: missing expected rest duration digit\n");
-		exit(1);
-	}
+	if (str[1] < '0' || str[1] > '5')
+		melody_error(str, "missing expected rest duration digit");
 	dur_basic = str[1] - '0';
 	switch (str[2]) {
 	case '.':
@@ -174,7 +171,7 @@
 		/* real stuff */
 		switch (*cp) {
 		case '*':
-			process_octave_cmd(cp[1]);
+			process_octave_cmd(cp);
 			cp += 2;
 			continue;
 		case 'c':
@@ -204,60 +201,40 @@
 				cp++;
 				continue;
 			}
-			if (!isdigit(*cp)) {
-				fprintf(stderr,
-				"melody error: invalid character after 'V'\n");
-				exit(1);
-			}
+			if (!isdigit(*cp))
+				melody_error(cp, "invalid character after 'V'");
 			if (*cp == '1' && cp[1] >= '0' && cp[1] <= '5')
 				cp += 2;
 			else
 				cp++;
 			continue;
 		case '(':
-			if (repeat_start_ptr) {
-				fprintf(stderr,
-					"melody error: nested repeat\n");
-				exit(1);
-			}
+			if (repeat_start_ptr)
+				melody_error(cp, "nested repeat");
 			cp++;
 			repeat_start_ptr = cp;
 			repeat_start_octave = cur_octave;
 			repeat_count = 0;
 			continue;
 		case '@':
-			if (!repeat_start_ptr) {
-				fprintf(stderr,
-				"melody error: '@' not in repeat block\n");
-				exit(1);
-			}
+			if (!repeat_start_ptr)
+				melody_error(cp, "'@' not in repeat block");
 			cp++;
-			if (!isdigit(*cp)) {
-				fprintf(stderr,
-				"melody error: '@' not followed by digit\n");
-				exit(1);
-			}
+			if (!isdigit(*cp))
+				melody_error(cp, "'@' not followed by digit");
 			rpt_set = *cp - '0';
-			if (!rpt_set) {
-				fprintf(stderr,
-			"melody error: infinite repeat not supported\n");
-				exit(1);
-			}
+			if (!rpt_set)
+				melody_error(cp,
+					"infinite repeat not supported");
 			cp++;
 			if (!repeat_count)
 				repeat_count = rpt_set;
 			continue;
 		case ')':
-			if (!repeat_start_ptr) {
-				fprintf(stderr,
-				"melody error: ')' without opening '('\n");
-				exit(1);
-			}
-			if (!repeat_count) {
-				fprintf(stderr,
-				"melody error: repeat block without count\n");
-				exit(1);
-			}
+			if (!repeat_start_ptr)
+				melody_error(cp, "')' without opening '('");
+			if (!repeat_count)
+				melody_error(cp, "repeat block without count");
 			repeat_count--;
 			if (repeat_count) {
 				cp = repeat_start_ptr;
@@ -268,9 +245,7 @@
 			}
 			continue;
 		default:
-			fprintf(stderr,
-				"melody error: non-understood character\n");
-			exit(1);
+			melody_error(cp, "non-understood character");
 		}
 	}
 }