Initial work on the WBT parser and its test suite

2026-06-25 22:45:08 +03:00
commit 94cc652049
10 changed files with 219 additions and 0 deletions
@@ -0,0 +1,93 @@
+module;
+#include <fstream>
+#include <iostream>
+
+// This module is the transpiler from WBT to HTML for site build
+export module wbt;
+
+export enum WBT_States {
+    WBT_STATE_INIT,
+    WBT_STATE_OPEN,
+    WBT_STATE_EXPRESSION,
+    WBT_STATE_CLOSE,
+};
+
+export class WBT_Parser {
+    std::istream& input;
+    std::ostream& output;
+public:
+    explicit WBT_Parser(
+        std::istream& i,
+        std::ostream& o
+    )
+        : input(i), output(o) {
+    }
+
+    void output_char(const char c) const {
+        output << c;
+    }
+
+    static void error(const std::string& msg, const int line, const int column) {
+        std::cerr << "Error (" << line << "," << column << "): " << msg << std::endl;
+    }
+
+    void eval(const std::string& expr) const {
+        output << "[EXPR: " << expr << "]";
+    }
+
+    void parse() const {
+        auto state = WBT_STATE_INIT;
+        std::string expr;
+        auto line = 1;
+        auto column = 1;
+        while (input.peek() != std::char_traits<char>::eof()) {
+            char c;
+            input.get(c);
+            // State machine
+            switch (state) {
+                case WBT_STATE_INIT:
+                    if (c == '{') {
+                        state = WBT_STATE_OPEN;
+                    } else {
+                        output_char(c);
+                    }
+                    break;
+                case WBT_STATE_OPEN:
+                    if (c == '{') {
+                        state = WBT_STATE_EXPRESSION;
+                    } else {
+                        output_char('{');
+                        output_char(c);
+                        state = WBT_STATE_INIT;
+                    }
+                    break;
+                case WBT_STATE_EXPRESSION:
+                    if (c == '}') {
+                        state = WBT_STATE_CLOSE;
+                    } else if (c == '{') {
+                        error("Invalid character inside of expression", line, column);
+                        return;
+                    } else {
+                        expr += c;
+                    }
+                    break;
+                case WBT_STATE_CLOSE:
+                    if (c == '}') {
+                        eval(expr);
+                        expr.clear();
+                        state = WBT_STATE_INIT;
+                    } else {
+                        error("Unclosed expression", line, column);
+                        return;
+                    }
+                    break;
+            }
+            if (c == '\n') {
+                line++;
+                column = 1;
+            } else {
+                column++;
+            }
+        }
+    }
+};