feat: add -a flag to print the AST

src/main.cpp

@@ -4,6 +4,7 @@
 #include "parser/Parser.h"
 #include "read.hpp"
 #include "utils/StdOut.h"
+#include "utils/printAST.h"
 #include "utils/printTokens.h"
 #include <getopt.h>
 #include <iostream>
@@ -12,18 +13,25 @@ int main(int argc, char *argv[]) {
     std::cout << "Yasi v0.0.0\n";
 
     bool displayTokens = false;
+    bool displayAST = false;
     StdOut *stdOut;
 
     int opt;
-    while ((opt = getopt(argc, argv, "t")) != -1) {
+    while ((opt = getopt(argc, argv, "at")) != -1) {
         switch (opt) {
             case 't':
                 displayTokens = true;
-                stdOut = new StdOut;
+                break;
+            case 'a':
+                displayAST = true;
                 break;
         }
     }
 
+    if (displayTokens || displayAST) {
+        stdOut = new StdOut;
+    }
+
     std::string userInput;
     while (true) {
         try {
@@ -38,7 +46,13 @@ int main(int argc, char *argv[]) {
             if (displayTokens) {
                 printTokens(stdOut, tokens);
             }
-            auto result = Evaluate::evaluate(Parser::parse(tokens));
+
+            auto ast = Parser::parse(tokens);
+            if (displayAST) {
+                print_ast(stdOut, ast);
+            }
+
+            auto result = Evaluate::evaluate(ast);
             std::cout << result.token.token << '\n';
         } catch (SyntaxError &error) {
             std::cout << "SyntaxError (" << error.line

src/utils/printAST.cpp

@@ -0,0 +1,31 @@
+#include "printAST.h"
+#include "parser/SyntaxTreeNode.h"
+#include <string>
+
+std::string parse_ast(SyntaxTreeNode ast, int level) {
+    std::string output;
+    std::string tabs;
+
+    for (int i = 0; i < level; i++) tabs = tabs + "\t";
+    tabs = tabs + "-> ";
+
+    if (!ast.children.empty()) {
+        output = tabs + "Node (" + ast.token.token + ")\n";
+    } else {
+        std::string type;
+        if (ast.token.type == Token::Integer) type = "Integer";
+        else if (ast.token.type == Token::String) type = "String";
+        else type = "Symbol";
+        return tabs + type + " (" + ast.token.token + ")\n";
+    }
+
+    for (const auto child: ast.children) {
+        output = output + parse_ast(child, level + 1);
+    }
+
+    return output;
+}
+
+void print_ast(OutputSource *outputSource, SyntaxTreeNode ast) {
+    outputSource->out(parse_ast(ast, 0));
+}

src/utils/printAST.h

@@ -0,0 +1,10 @@
+#ifndef YASI_PRINTAST_H
+#define YASI_PRINTAST_H
+
+#include "parser/SyntaxTreeNode.h"
+#include "utils/OutputSource.h"
+
+void print_ast(OutputSource *outputSource, SyntaxTreeNode ast);
+
+#endif
+

tests/print_ast_test.cpp

@@ -0,0 +1,54 @@
+#include "parser/SyntaxTreeNode.h"
+#include "utils/OutputSource.h"
+#include "utils/printAST.h"
+#include "gmock/gmock.h"
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+#include <memory>
+
+class MockOutputSource : public OutputSource {
+public:
+    MOCK_METHOD(void, out, (std::string out), (override));
+};
+
+
+TEST(print_ast_test, ShouldPrintSimpleAST) {
+    // (+ 1 2)
+    const SyntaxTreeNode ast = SyntaxTreeNode(
+            Token(Token::Symbol, "+"),
+            {
+                    SyntaxTreeNode(Token(Token::Integer, "1")),
+                    SyntaxTreeNode(Token(Token::Integer, "2")),
+            });
+    std::shared_ptr<MockOutputSource> mockOutputSource(new MockOutputSource);
+
+    EXPECT_CALL(*mockOutputSource, out("-> Node (+)\n"
+                                       "\t-> Integer (1)\n"
+                                       "\t-> Integer (2)\n"));
+    print_ast(mockOutputSource.get(), ast);
+}
+
+TEST(print_ast_test, ShouldPrintNestedAST) {
+    // (+ (* 5 2) 4)
+    const SyntaxTreeNode ast = SyntaxTreeNode(
+            Token(Token::Symbol, "+"),
+            {
+                    SyntaxTreeNode(
+                            Token(Token::Symbol, "*"),
+                            {
+                                    SyntaxTreeNode(Token(Token::Integer, "5")),
+                                    SyntaxTreeNode(Token(Token::Integer, "2")),
+                            }),
+                    SyntaxTreeNode(Token(Token::Integer, "4")),
+            });
+    const std::string expectedOutput = "-> Node (+)\n"
+                                       "\t-> Node (*)\n"
+                                       "\t\t-> Integer (5)\n"
+                                       "\t\t-> Integer (2)\n"
+                                       "\t-> Integer (4)\n";
+
+    std::shared_ptr<MockOutputSource> mockOutputSource(new MockOutputSource);
+
+    EXPECT_CALL(*mockOutputSource, out(expectedOutput));
+    print_ast(mockOutputSource.get(), ast);
+}