parser: add support for comments

Add the ability for input files to have comments in them.  A comment
begins with a '#' character and continues through the end of the line.

Signed-off-by: Alex Elder <elder@linaro.org>
Message-Id: <20211001232338.769309-21-elder@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

parser.c

@@ -145,6 +145,26 @@ static void symbol_add(const char *name, enum token_id token_id, ...)
 	va_end(ap);
 }
 
+/* Skip over white space and comments (which start with '#', end with '\n') */
+static bool skip(char ch)
+{
+	static bool in_comment = false;
+
+	if (in_comment) {
+		if (ch == '\n')
+			in_comment = false;
+		return true;
+	}
+
+	if (isspace(ch))
+		return true;
+
+	if (ch == '#')
+		in_comment = true;
+
+	return in_comment;
+}
+
 static struct token yylex()
 {
 	struct symbol *sym;
@@ -154,7 +174,7 @@ static struct token yylex()
 	int base;
 	char ch;
 
-	while ((ch = input()) && isspace(ch))
+	while ((ch = input()) && skip(ch))
 		;
 
 	if (isalpha(ch)) {

tests/comments.qmi

@@ -0,0 +1,28 @@
+# This is a comment at the beginning of the file
+#
+#############
+package test;
+#############
+
+const TEST_REQUEST_RESPONSE = 35;	# Skip me!!! # Skip me!!!
+
+struct qmi_result {
+	u16 result;
+  # No limit on
+	u16#     where     comments
+				# can go
+error;
+};
+
+request test_request {
+	required u8 test_number = 0x12;
+} = 0x23;	# Skip me!!! # Skip me!!!
+
+response test_response {
+	required qmi_result r = 2;
+} = 043;
+
+indication test_indication {
+	optional u64 value = 0x99;
+} = 0x7;
+######## End the file with a comment