Started a new parser using ragel. It can parse the slides but without json. Need to re-read the ragel manual to get it fully working.

Makefile

@@ -9,7 +9,10 @@ else
 	sh -x ./scripts/reset_build.sh
 endif
 
-build:
+%.cpp : %.rl
+	ragel -o $@ $<
+
+build: md_parser.cpp
 	meson compile -j 10 -C builddir
 
 release_build:
@@ -41,6 +44,9 @@ debug_run: build
 clean:
 	meson compile --clean -C builddir
 
+test: build
+	./builddir/runtests -e
+
 debug_test: build
 	gdb --nx -x .gdbinit --ex run --args builddir/runtests -e
 

backup_parser.cpp

@@ -0,0 +1,62 @@
+#include "parser.hpp"
+#include "dbc.hpp"
+#include <filesystem>
+#include <fstream>
+#include <iostream>
+#include <nlohmann/json.hpp>
+#include <memory>
+#include <string_view>
+#include <ranges>
+
+using std::shared_ptr, std::string, nlohmann::json, std::string_view;
+namespace fs = std::filesystem;
+
+shared_ptr<SlideDeck> parse_slides(const string& md_file) {
+  shared_ptr<SlideDeck> deck = std::make_shared<SlideDeck>();
+
+  dbc::check(fs::exists(md_file), "md file missing");
+
+  auto size = fs::file_size(md_file);
+  string line(size, '\0');
+  bool started = false;
+  json config;
+
+  if(std::ifstream in_file{md_file, std::ios::binary}) {
+    while(std::getline(in_file, line)) {
+      if(line == "{") {
+        string json_data;
+
+        do {
+          json_data += line;
+        } while (std::getline(in_file, line) && line != "}");
+
+        json_data += "}";
+
+        config = json::parse(json_data);
+        std::cout << "JSON: " << config << '\n';
+      } else if(line == "===") {
+        deck->config = config;
+        fmt::println("START");
+        started = true;
+      } else if(line == "---") {
+        fmt::println("START SLIDE");
+      } else {
+        if(started) {
+          string title = line;
+          string content;
+
+          while(std::getline(in_file, line) && line != "---") {
+            content += line + "\n";
+          }
+
+          deck->slides.emplace_back(title, content, config);
+          config = json::parse("{}");
+        } else {
+          fmt::println("JUNK: {}", line);
+        }
+      }
+    }
+  }
+
+  return deck;
+}

md_parser.cpp

@@ -0,0 +1,222 @@
+
+#line 1 "md_parser.rl"
+#include <fmt/core.h>
+#include <iostream>
+
+
+#line 38 "md_parser.rl"
+
+
+
+#line 7 "md_parser.cpp"
+static const char _Parser_actions[] = {
+	0, 1, 0, 1, 3, 1, 4, 2, 
+	0, 1, 2, 0, 2, 2, 1, 0, 
+	2, 2, 0, 2, 3, 5
+};
+
+static const char _Parser_key_offsets[] = {
+	0, 0, 1, 2, 3, 4, 10, 11, 
+	18, 22, 29, 31, 33, 34
+};
+
+static const char _Parser_trans_keys[] = {
+	61, 61, 61, 10, 10, 32, 35, 42, 
+	9, 13, 10, 10, 32, 35, 42, 45, 
+	9, 13, 10, 32, 9, 13, 10, 32, 
+	35, 42, 45, 9, 13, 10, 45, 10, 
+	45, 10, 10, 32, 35, 42, 45, 9, 
+	13, 0
+};
+
+static const char _Parser_single_lengths[] = {
+	0, 1, 1, 1, 1, 4, 1, 5, 
+	2, 5, 2, 2, 1, 5
+};
+
+static const char _Parser_range_lengths[] = {
+	0, 0, 0, 0, 0, 1, 0, 1, 
+	1, 1, 0, 0, 0, 1
+};
+
+static const char _Parser_index_offsets[] = {
+	0, 0, 2, 4, 6, 8, 14, 16, 
+	23, 27, 34, 37, 40, 42
+};
+
+static const char _Parser_indicies[] = {
+	0, 1, 2, 1, 3, 1, 4, 1, 
+	7, 6, 8, 9, 6, 5, 11, 10, 
+	7, 6, 8, 9, 12, 6, 5, 13, 
+	6, 6, 5, 7, 6, 14, 15, 12, 
+	6, 5, 11, 16, 10, 11, 17, 10, 
+	18, 10, 7, 6, 8, 9, 12, 6, 
+	5, 0
+};
+
+static const char _Parser_trans_targs[] = {
+	2, 0, 3, 4, 5, 6, 8, 9, 
+	8, 8, 6, 7, 10, 9, 8, 8, 
+	11, 12, 13
+};
+
+static const char _Parser_trans_actions[] = {
+	0, 0, 0, 0, 5, 1, 1, 0, 
+	13, 16, 0, 3, 1, 3, 7, 10, 
+	0, 0, 19
+};
+
+static const int Parser_start = 1;
+static const int Parser_first_final = 13;
+static const int Parser_error = 0;
+
+static const int Parser_en_main = 1;
+
+
+#line 41 "md_parser.rl"
+
+
+bool Parser::parse(const std::string& input) {
+  int cs = 0;
+  const char *start = nullptr;
+  const char *begin = input.data();
+  const char *p = input.data();
+  const char *pe = p + input.size();
+  const char *eof = p + input.size(); (void)eof;
+  std::string tk;
+
+  
+#line 81 "md_parser.cpp"
+	{
+	cs = Parser_start;
+	}
+
+#line 53 "md_parser.rl"
+  
+#line 84 "md_parser.cpp"
+	{
+	int _klen;
+	unsigned int _trans;
+	const char *_acts;
+	unsigned int _nacts;
+	const char *_keys;
+
+	if ( p == pe )
+		goto _test_eof;
+	if ( cs == 0 )
+		goto _out;
+_resume:
+	_keys = _Parser_trans_keys + _Parser_key_offsets[cs];
+	_trans = _Parser_index_offsets[cs];
+
+	_klen = _Parser_single_lengths[cs];
+	if ( _klen > 0 ) {
+		const char *_lower = _keys;
+		const char *_mid;
+		const char *_upper = _keys + _klen - 1;
+		while (1) {
+			if ( _upper < _lower )
+				break;
+
+			_mid = _lower + ((_upper-_lower) >> 1);
+			if ( (*p) < *_mid )
+				_upper = _mid - 1;
+			else if ( (*p) > *_mid )
+				_lower = _mid + 1;
+			else {
+				_trans += (unsigned int)(_mid - _keys);
+				goto _match;
+			}
+		}
+		_keys += _klen;
+		_trans += _klen;
+	}
+
+	_klen = _Parser_range_lengths[cs];
+	if ( _klen > 0 ) {
+		const char *_lower = _keys;
+		const char *_mid;
+		const char *_upper = _keys + (_klen<<1) - 2;
+		while (1) {
+			if ( _upper < _lower )
+				break;
+
+			_mid = _lower + (((_upper-_lower) >> 1) & ~1);
+			if ( (*p) < _mid[0] )
+				_upper = _mid - 2;
+			else if ( (*p) > _mid[1] )
+				_lower = _mid + 2;
+			else {
+				_trans += (unsigned int)((_mid - _keys)>>1);
+				goto _match;
+			}
+		}
+		_trans += _klen;
+	}
+
+_match:
+	_trans = _Parser_indicies[_trans];
+	cs = _Parser_trans_targs[_trans];
+
+	if ( _Parser_trans_actions[_trans] == 0 )
+		goto _again;
+
+	_acts = _Parser_actions + _Parser_trans_actions[_trans];
+	_nacts = (unsigned int) *_acts++;
+	while ( _nacts-- > 0 )
+	{
+		switch ( *_acts++ )
+		{
+	case 0:
+#line 12 "md_parser.rl"
+	{ start = p; }
+	break;
+	case 1:
+#line 13 "md_parser.rl"
+	{ fmt::println("TITLE"); }
+	break;
+	case 2:
+#line 14 "md_parser.rl"
+	{ fmt::println("ENUM"); }
+	break;
+	case 3:
+#line 15 "md_parser.rl"
+	{
+    tk = input.substr(start - begin, p - start);
+    std::cout << "CONTENT:" << std::quoted(tk) << '\n';
+  }
+	break;
+	case 4:
+#line 19 "md_parser.rl"
+	{ fmt::println("----- START"); }
+	break;
+	case 5:
+#line 20 "md_parser.rl"
+	{ fmt::println("END"); }
+	break;
+#line 178 "md_parser.cpp"
+		}
+	}
+
+_again:
+	if ( cs == 0 )
+		goto _out;
+	if ( ++p != pe )
+		goto _resume;
+	_test_eof: {}
+	_out: {}
+	}
+
+#line 54 "md_parser.rl"
+
+  bool good = pe - p == 0;
+
+  if(good) {
+    finalize();
+  } else {
+    error = true;
+    std::cout << "!!!!!!!!!!!!!!!!!!!!!! error at:";
+    std::cout << p;
+  }
+  return good;
+}

md_parser.rl

@@ -0,0 +1,65 @@
+#include <fmt/core.h>
+#include <iostream>
+
+%%{
+  machine Parser;
+  alphtype char;
+
+  action token {
+    tk = input.substr(start - begin, fpc - start);
+    std::cout << "TOKEN: " << std::quoted(tk) << '\n';
+  }
+  action mark { start = fpc; }
+  action title { fmt::println("TITLE"); }
+  action enum { fmt::println("ENUM"); }
+  action content {
+    tk = input.substr(start - begin, fpc - start);
+    std::cout << "CONTENT:" << std::quoted(tk) << '\n';
+  }
+  action start { fmt::println("----- START"); }
+  action end { fmt::println("END"); }
+  action plain { fmt::println("PLAIN"); }
+
+  eol = "\n";
+  start = "===" eol $start;
+  end = "---" eol $end;
+  pound = "#" $title;
+  asterisk = "*" $enum;
+  content = (any+ -- (eol|end)) >mark %content;
+
+  title = pound space* content  eol;
+  enum = asterisk space* content eol;
+  line = space* content eol;
+  blank = space* eol;
+
+  slide = (title | enum | line | blank)+ end;
+
+  main := start (slide)+;
+}%%
+
+%% write data;
+
+
+bool Parser::parse(const std::string& input) {
+  int cs = 0;
+  const char *start = nullptr;
+  const char *begin = input.data();
+  const char *p = input.data();
+  const char *pe = p + input.size();
+  const char *eof = p + input.size(); (void)eof;
+  std::string tk;
+
+  %% write init;
+  %% write exec;
+
+  bool good = pe - p == 0;
+
+  if(good) {
+    finalize();
+  } else {
+    error = true;
+    std::cout << "!!!!!!!!!!!!!!!!!!!!!! error at:";
+    std::cout << p;
+  }
+  return good;
+}

meson.build

@@ -82,17 +82,17 @@ dependencies += [
 sources = [
   'dbc.cpp',
   'backend.cpp',
-  'main.cpp',
   'control_ui.cpp',
   'slides_ui.cpp',
-  'parser.cpp'
+  'parser.cpp',
+  'backup_parser.cpp',
 ]
 
 tests = [
-  'tests/sample.cpp'
+  'tests/parsing.cpp'
 ]
 
-executable('besos', sources,
+executable('besos', sources + ['main.cpp'],
   cpp_args: cpp_args,
   link_args: link_args,
   override_options: exe_defaults,

parser.cpp

@@ -1,60 +1,24 @@
-#include "parser.hpp"
-#include "dbc.hpp"
-#include <filesystem>
+#include <fmt/core.h>
+#include <numeric>
+#include <cassert>
 #include <fstream>
 #include <iostream>
-#include <nlohmann/json.hpp>
-#include <memory>
-
-using std::shared_ptr, std::string, nlohmann::json;
-namespace fs = std::filesystem;
-
-shared_ptr<SlideDeck> parse_slides(const string& md_file) {
-  shared_ptr<SlideDeck> deck = std::make_shared<SlideDeck>();
-
-  dbc::check(fs::exists(md_file), "md file missing");
-
-  auto size = fs::file_size(md_file);
-  string line(size, '\0');
-  bool started = false;
-  json config;
-
-  if(std::ifstream in_file{md_file, std::ios::binary}) {
-    while(std::getline(in_file, line)) {
-      if(line == "{") {
-        string json_data;
+#include "parser.hpp"
+#include "dbc.hpp"
 
-        do {
-          json_data += line;
-        } while (std::getline(in_file, line) && line != "}");
+#include "./md_parser.cpp"
 
-        json_data += "}";
+std::string load_file(const std::string& md_file) {
+  std::ifstream in_file{md_file, std::ios::binary};
+  dbc::check(bool(in_file), fmt::format("failed to load {}", md_file));
 
-        config = json::parse(json_data);
-        std::cout << "JSON: " << config << '\n';
-      } else if(line == "===") {
-        deck->config = config;
-        fmt::println("START");
-        started = true;
-      } else if(line == "---") {
-        fmt::println("START SLIDE");
-      } else {
-        if(started) {
-          string title = line;
-          string content;
+  return std::string(std::istreambuf_iterator<char>(in_file), std::istreambuf_iterator<char>());
+}
 
-          while(std::getline(in_file, line) && line != "---") {
-            content += line + "\n";
-          }
+Parser::Parser()
+{
 
-          deck->slides.emplace_back(title, content, config);
-          config = json::parse("{}");
-        } else {
-          fmt::println("JUNK: {}", line);
-        }
-      }
-    }
-  }
+}
 
-  return deck;
+void Parser::finalize() {
 }

parser.hpp

@@ -4,3 +4,13 @@
 #include "slides_ui.hpp"
 
 std::shared_ptr<SlideDeck> parse_slides(const std::string& md_file);
+
+std::string load_file(const std::string& md_file);
+
+struct Parser {
+  bool error = false;
+
+  Parser();
+  bool parse(const std::string& input);
+  void finalize();
+};

sample/01-a-good-first-program.md

@@ -1,33 +1,27 @@
-{
-    "title": "1: A Good First Program",
-    "summary": "If you skipped Exercise 0, then you are not doing this book right."
-}
 ===
-1: A Good First Program
+# 1: A Good First Program
 
 * The key is this
 * That's what we want
 ---
-What You Should See
+# What You Should See
 
 Yes, but with more feeling.
 ---
-{
-"bg_color": [255, 0, 0, 255]
-}
-Study Drills
+# Study Drills
 
 Besos would be proud.
 ---
-Common Student Questions
+# Common Student Questions
 
-- This again.
-- That too.
+* This again.
+* That too.
 ---
-The Blue Plus
+# The Blue Plus
 
 _You must find it_.
 ---
-The End
+# The End
 
-# See You Soon!
+See You Soon!
+---

sample/with_json.md

@@ -0,0 +1,34 @@
+{
+    "title": "1: A Good First Program",
+    "summary": "If you skipped Exercise 0, then you are not doing this book right."
+}
+===
+# 1: A Good First Program
+
+* The key is this
+* That's what we want
+---
+# What You Should See
+
+Yes, but with more feeling.
+---
+{
+"bg_color": [255, 0, 0, 255]
+}
+# Study Drills
+
+Besos would be proud.
+---
+# Common Student Questions
+
+- This again.
+- That too.
+---
+# The Blue Plus
+
+_You must find it_.
+---
+# The End
+
+See You Soon!
+---

tests/parsing.cpp

@@ -0,0 +1,19 @@
+#include <catch2/catch_test_macros.hpp>
+#include "guecs/sfml/backend.hpp"
+#include <fmt/core.h>
+#include <string>
+#include "parser.hpp"
+
+TEST_CASE("parse a simple example", "[parsing]") {
+  sfml::Backend backend;
+  guecs::init(&backend);
+
+  auto data = parse_slides("./sample/01-a-good-first-program.md");
+  REQUIRE(data->slides.size() > 0);
+
+  auto contents = load_file("./sample/01-a-good-first-program.md");
+  Parser rp;
+  rp.parse(contents);
+
+  REQUIRE(!rp.error);
+}