add syntax highlighting (WIP)

src/devtools/syntax_highlighting.cpp

@@ -0,0 +1,72 @@
+#include "syntax_highlighting.hpp"
+
+#include "coders/commons.hpp"
+#include "coders/lua_parsing.hpp"
+#include "graphics/core/Font.hpp"
+
+using namespace devtools;
+
+static std::unique_ptr<FontStylesScheme> build_styles(
+    const std::vector<lua::Token>& tokens
+) {
+    FontStylesScheme styles {
+        {
+            {false, false, glm::vec4(0.8f, 0.8f, 0.8f, 1)}, // default
+            {true, false, glm::vec4(0.9, 0.6f, 0.4f, 1)},   // keyword
+            {false, false, glm::vec4(0.4, 0.8f, 0.5f, 1)},  // string
+            {false, false, glm::vec4(0.3, 0.3f, 0.3f, 1)},  // comment
+            {false, false, glm::vec4(0.4, 0.45f, 0.5f, 1)}, // self
+            {true, false, glm::vec4(1.0f, 0.2f, 0.1f, 1)}, // unexpected
+        }, 
+        {}
+    };
+    size_t offset = 0;
+    for (int i = 0; i < tokens.size(); i++) {
+        const auto& token = tokens.at(i);
+        if (token.tag != lua::TokenTag::KEYWORD &&
+            token.tag != lua::TokenTag::STRING &&
+            token.tag != lua::TokenTag::INTEGER &&
+            token.tag != lua::TokenTag::NUMBER &&
+            token.tag != lua::TokenTag::COMMENT &&
+            token.tag != lua::TokenTag::UNEXPECTED) {
+            continue;
+        }
+        if (token.start.pos > offset) {
+            int n = token.start.pos - offset;
+            styles.map.insert(styles.map.end(), token.start.pos - offset, 0);
+        }
+        offset = token.end.pos;
+        int styleIndex;
+        switch (token.tag) {
+            case lua::TokenTag::KEYWORD: styleIndex = 1; break;
+            case lua::TokenTag::STRING:
+            case lua::TokenTag::INTEGER:
+            case lua::TokenTag::NUMBER: styleIndex = 2; break;
+            case lua::TokenTag::COMMENT: styleIndex = 3; break;
+            case lua::TokenTag::UNEXPECTED: styleIndex = 5; break;
+            default:
+                styleIndex = 0;
+                break;
+        }
+        styles.map.insert(
+            styles.map.end(), token.end.pos - token.start.pos, styleIndex
+        );
+    }
+    styles.map.push_back(0);
+    return std::make_unique<FontStylesScheme>(std::move(styles));
+}
+
+std::unique_ptr<FontStylesScheme> devtools::syntax_highlight(
+    const std::string& lang, std::string_view source
+) {
+    try {
+        if (lang == "lua") {
+            auto tokens = lua::tokenize("<string>", source);
+            return build_styles(tokens);
+        } else {
+            return nullptr;
+        }
+    } catch (const parsing_error& err) {
+        return nullptr;
+    }
+}