Refactoring some stuff in the parser lib, moving functions out of headers

parser/src/length.c

@@ -0,0 +1,43 @@
+#include "./length.h"
+#include "./point.h"
+
+bool length_is_undefined(Length length)
+{
+	return (length.bytes == 0 && length.extent.column != 0);
+}
+
+Length length_min(Length len1, Length len2)
+{
+	return ((len1.bytes < len2.bytes) ? len1 : len2);
+}
+
+Length length_add(Length len1, Length len2)
+{
+	Length result;
+
+	result.bytes = len1.bytes + len2.bytes;
+	result.extent = point_add(len1.extent, len2.extent);
+	return (result);
+}
+
+Length length_sub(Length len1, Length len2)
+{
+	Length result;
+
+	result.bytes = len1.bytes - len2.bytes;
+	result.extent = point_sub(len1.extent, len2.extent);
+	return (result);
+}
+
+Length length_zero(void)
+{
+	return ((Length){0, {0, 0}});
+}
+
+Length length_saturating_sub(Length len1, Length len2)
+{
+	if (len1.bytes > len2.bytes)
+		return (length_sub(len1, len2));
+	else
+		return (length_zero());
+}