From 3bebedf1f810c3d6149b59b75923bf4ee2442696 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Antonio=20Ni=C3=B1o=20D=C3=ADaz?= <antonio_nd@outlook.com>
Date: Thu, 22 Feb 2018 22:11:30 +0000
Subject: [PATCH] Handle newlines and comments correctly
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Newlines have to be handled before comments or comments won't be able to
handle line endings that don't include at least one LF character.

Also, document an obscure comment syntax: Anything that follows a '*'
placed at the start of a line is also a comment until the end of the
line.

Signed-off-by: Antonio Niño Díaz <antonio_nd@outlook.com>
---
 docs/rgbasm.5.html |  6 ++++++
 src/asm/lexer.c    | 40 +++++++++++++++++++++++++++++++++-------
 src/asm/rgbasm.5   |  6 ++++++
 3 files changed, 45 insertions(+), 7 deletions(-)

diff --git a/docs/rgbasm.5.html b/docs/rgbasm.5.html
index a9194599..88776565 100644
--- a/docs/rgbasm.5.html
+++ b/docs/rgbasm.5.html
@@ -42,6 +42,12 @@ Example:
 <div class="Pp"></div>
 All pseudo&#x2010;ops, mnemonics and registers (reserved keywords) are
   case&#x2010;insensitive and all labels are case&#x2010;sensitive.
+<div class="Pp"></div>
+There are two syntaxes for comments. In both cases, a comment ends at the end of
+  the line. The most common one is: anything that follows a semicolon
+  &quot;;&quot; (that isn't inside a string) is a comment. There is another
+  format: anything that follows a &quot;*&quot; that is placed right at the
+  start of a line is a comment.
 <h2 class="Ss" title="Ss" id="Sections"><a class="selflink" href="#Sections">Sections</a></h2>
 Before you can start writing code, you must define a section. This tells the
   assembler what kind of information follows and, if it is code, where to put
diff --git a/src/asm/lexer.c b/src/asm/lexer.c
index 1462383a..0c728784 100644
--- a/src/asm/lexer.c
+++ b/src/asm/lexer.c
@@ -159,6 +159,8 @@ YY_BUFFER_STATE yy_create_buffer(FILE *f)
 	pBuffer->pBuffer[size + 1] = 0;
 	pBuffer->nBufferSize = size + 1;
 
+	/* Convert all line endings to LF and spaces */
+
 	char *mem = pBuffer->pBuffer;
 	uint32_t instring = 0;
 
@@ -171,20 +173,44 @@ YY_BUFFER_STATE yy_create_buffer(FILE *f)
 		} else if (instring) {
 			mem += 1;
 		} else {
-			if ((mem[0] == 10 && mem[1] == 13)
-				|| (mem[0] == 13 && mem[1] == 10)) {
+			/* LF CR and CR LF */
+			if (((mem[0] == 10) && (mem[1] == 13))
+			 || ((mem[0] == 13) && (mem[1] == 10))) {
 				mem[0] = ' ';
 				mem[1] = '\n';
 				mem += 2;
-			} else if (mem[0] == 10 || mem[0] == 13) {
+			/* LF and CR */
+			} else if ((mem[0] == 10) || (mem[0] == 13)) {
 				mem[0] = '\n';
 				mem += 1;
-			} else if (mem[0] == '\n' && mem[1] == '*') {
+			} else {
 				mem += 1;
-				while (!(*mem == '\n' || *mem == '\0'))
+			}
+		}
+	}
+
+	/* Remove comments */
+
+	mem = pBuffer->pBuffer;
+	instring = 0;
+
+	while (*mem) {
+		if (*mem == '\"')
+			instring = 1 - instring;
+
+		if ((mem[0] == '\\') && (mem[1] == '\"' || mem[1] == '\\')) {
+			mem += 2;
+		} else if (instring) {
+			mem += 1;
+		} else {
+			/* Comments that start with ; anywhere in a line */
+			if (*mem == ';') {
+				while (!((*mem == '\n') || (*mem == '\0')))
 					*mem++ = ' ';
-			} else if (*mem == ';') {
-				while (!(*mem == '\n' || *mem == '\0'))
+			/* Comments that start with * at the start of a line */
+			} else if ((mem[0] == '\n') && (mem[1] == '*')) {
+				mem += 1;
+				while (!((*mem == '\n') || (*mem == '\0')))
 					*mem++ = ' ';
 			} else {
 				mem += 1;
diff --git a/src/asm/rgbasm.5 b/src/asm/rgbasm.5
index b3a00fd9..64a028fa 100644
--- a/src/asm/rgbasm.5
+++ b/src/asm/rgbasm.5
@@ -30,6 +30,12 @@ Example:
 .Pp
 All pseudo‐ops, mnemonics and registers (reserved keywords) are case‐insensitive
 and all labels are case‐sensitive.
+.Pp
+There are two syntaxes for comments. In both cases, a comment ends at the end of
+the line. The most common one is: anything that follows a semicolon
+\[dq]\&;\[dq] (that isn't inside a string) is a comment. There is another
+format: anything that follows a \[dq]*\[dq] that is placed right at the start of
+a line is a comment.
 .Ss Sections
 Before you can start writing code, you must define a section.
 This tells the assembler what kind of information follows and, if it is code,