From c592ef5369a0c1dfe0feab4bff6f5186a5cbb897 Mon Sep 17 00:00:00 2001
From: overflowerror <mail@overflowerror.com>
Date: Thu, 20 May 2021 17:04:16 +0200
Subject: [PATCH] basic scanner done

---
 src/scanner.l | 70 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 70 insertions(+)
 create mode 100644 src/scanner.l

diff --git a/src/scanner.l b/src/scanner.l
new file mode 100644
index 0000000..4bc6adc
--- /dev/null
+++ b/src/scanner.l
@@ -0,0 +1,70 @@
+whitespace			[\n\t\r ]
+
+params_begin		"{$"
+params_end			"$}"
+
+section				"%%"
+
+statement_begin	"{%"
+statement_end		"%}"
+
+output_begin		"{{"
+output_end			"}}"
+
+block_end			"end"
+
+type_prefixes		"enum"|"struct"
+type_prefix			{type_prefixes}{whitespace}+
+type_pointer		{whitespace}*"*"
+type					{type_prefix}?[a-zA-Z0-9_]+{type_pointer}?
+
+%option noyywrap
+%option nodefault
+%option nounput
+%option noinput
+%option yylineno
+
+%x PARAMS
+%x STATEMENT
+%x OUTPUT
+%x META_SECTION
+%x MAIN_SECTION
+
+%s META_SECTION
+
+%%
+
+%{
+	#include <stdbool.h>
+	#include <stdlib.h>
+	#include <stdio.h>
+	
+	bool isMetaSection = true;
+%}
+
+<META_SECTION>{params_begin}		{ BEGIN(PARAMS); return PARAMS_BEGIN; }
+<META_SECTION>{statement_begin}	{ BEGIN(STATEMENT); return STATEMENT_BEGIN; }
+<META_SECTION>{section}				{ isMetaSection = false; BEGIN(MAIN_SECTION); }
+<META_SECTION>{output_begin}		{ fprintf(stderr, "error: output block not allowed in meta section (line %d)\n", yylineno); exit(1); }
+<META_SECTION>.						{ fprintf(stderr, "error: raw text not allowed in meta section (line %d)\n", yylineno); exit(1); }
+
+<PARAMS>{type}							{ return TEXT; }
+<PARAMS>{params_end}					{ BEGIN(META_SECTION); return PARAMS_END; }
+<PARAMS>","								{ return COMMA; }
+<PARAMS>{whitespace}+				{ /* ignore whitespaces */ }
+<PARAMS>$								{ return TEXT; /* catch $ as text */ }
+<PARAMS>.								{ fprintf(stderr, "error: illegal token '%s' in parameter block (line %d)\n", yytext, yylineno); exit(1); }
+
+<STATEMENT>[^%]+						{ return TEXT; }
+<STATEMENT>%							{ return TEXT; /* catch % as text */ }
+<STATEMENT>{statement_end}			{ if (isMetaSection) BEGIN(META_SECTION); else BEGIN(MAIN_SECTION); return STATEMENT_END; }
+
+<MAIN_SECTION>{params_begin}		{ fprintf(stderr, "warning: parameter block not allowed in main section (line %d); assuming to be text\n", yylineno); return TEXT; }
+<MAIN_SECTION>{statement_begin}	{ BEGIN(STATEMENT); return STATEMENT_BEGIN; }
+<MAIN_SECTION>{output_begin}		{ BEGIN(OUTPUT); return OUTPUT_BEGIN; }
+<MAIN_SECTION>.						{ return TEXT; }
+
+<OUTPUT>[^}]+							{ return TEXT; }
+<OUTPUT>{output_end}					{ BEGIN(MAIN_SECTION); return OUTPUT_END; }
+<OUTPUT>"}"								{ return TEXT; /* catch } as text */ }
+