Step 374: Add Scheme parser and pipeline routing

editor/CMakeLists.txt

@@ -2245,4 +2245,13 @@ target_link_libraries(step373_test PRIVATE
     tree_sitter_javascript tree_sitter_typescript
     tree_sitter_java tree_sitter_rust tree_sitter_go)
 
+add_executable(step374_test tests/step374_test.cpp)
+target_include_directories(step374_test PRIVATE src)
+target_link_libraries(step374_test PRIVATE
+    nlohmann_json::nlohmann_json
+    unofficial::tree-sitter::tree-sitter
+    tree_sitter_python tree_sitter_cpp tree_sitter_elisp
+    tree_sitter_javascript tree_sitter_typescript
+    tree_sitter_java tree_sitter_rust tree_sitter_go)
+
 # Step 12: Dear ImGui shell scaffolding created (main.cpp exists but not built due to dependencies)

editor/src/Pipeline.h

@@ -131,6 +131,10 @@ public:
             auto pr = CommonLispParser::parseCommonLispWithDiagnostics(source);
             diags = std::move(pr.diagnostics);
             return std::move(pr.module);
+        } else if (language == "scheme" || language == "scm") {
+            auto pr = SchemeParser::parseSchemeWithDiagnostics(source);
+            diags = std::move(pr.diagnostics);
+            return std::move(pr.module);
         }
         return nullptr;
     }

editor/src/ast/Parser.h

@@ -167,3 +167,4 @@ private:
 #include "ast/CParser.h"
 #include "ast/WatParser.h"
 #include "ast/CommonLispParser.h"
+#include "ast/SchemeParser.h"

editor/src/ast/SchemeParser.h

@@ -0,0 +1,461 @@
+#pragma once
+
+#include "ASTNode.h"
+#include "Module.h"
+#include "Function.h"
+#include "Variable.h"
+#include "Parameter.h"
+#include "Type.h"
+#include "Statement.h"
+#include "Expression.h"
+#include "AsyncNodes.h"
+#include "PreprocessorNodes.h"
+#include "Annotation.h"
+#include "../ast/Parser.h"
+#include <cctype>
+#include <string>
+#include <vector>
+
+class SchemeParser {
+public:
+    static std::unique_ptr<Module> parseScheme(const std::string& source) {
+        ParseResult result = parseSchemeWithDiagnostics(source);
+        return std::move(result.module);
+    }
+
+    static ParseResult parseSchemeWithDiagnostics(const std::string& source) {
+        ParseResult result;
+        result.module = std::make_unique<Module>();
+        result.module->id = IdGenerator::next("mod");
+        result.module->name = "parsed_scheme_module";
+        result.module->targetLanguage = "scheme";
+
+        std::vector<SExpr> forms = parseForms(source, result.diagnostics);
+        for (const auto& form : forms) {
+            convertTopLevelForm(form, result.module.get());
+        }
+        return result;
+    }
+
+private:
+    struct SExpr {
+        bool isList = false;
+        std::string atom;
+        std::vector<SExpr> list;
+    };
+
+    static bool isWhitespace(char c) {
+        return c == ' ' || c == '\t' || c == '\n' || c == '\r';
+    }
+
+    static bool isDelimiter(char c) {
+        return isWhitespace(c) || c == '(' || c == ')' || c == '\'' || c == '`' || c == ';';
+    }
+
+    static bool isInteger(const std::string& s) {
+        if (s.empty()) return false;
+        size_t i = (s[0] == '-' || s[0] == '+') ? 1 : 0;
+        if (i >= s.size()) return false;
+        for (; i < s.size(); ++i) {
+            if (!std::isdigit(static_cast<unsigned char>(s[i]))) return false;
+        }
+        return true;
+    }
+
+    static bool isFloat(const std::string& s) {
+        if (s.empty()) return false;
+        bool seenDot = false;
+        bool seenDigit = false;
+        size_t i = (s[0] == '-' || s[0] == '+') ? 1 : 0;
+        if (i >= s.size()) return false;
+        for (; i < s.size(); ++i) {
+            char c = s[i];
+            if (std::isdigit(static_cast<unsigned char>(c))) {
+                seenDigit = true;
+            } else if (c == '.' && !seenDot) {
+                seenDot = true;
+            } else {
+                return false;
+            }
+        }
+        return seenDigit && seenDot;
+    }
+
+    static bool isStringToken(const std::string& s) {
+        return s.size() >= 2 && s.front() == '"' && s.back() == '"';
+    }
+
+    static std::string canonicalHead(const std::string& symbol) {
+        size_t pos = symbol.rfind(':');
+        if (pos == std::string::npos) return symbol;
+        return symbol.substr(pos + 1);
+    }
+
+    static std::string atomText(const SExpr& expr) {
+        return expr.isList ? "" : expr.atom;
+    }
+
+    static std::string headSymbol(const SExpr& expr) {
+        if (!expr.isList || expr.list.empty() || expr.list[0].isList) return "";
+        return canonicalHead(expr.list[0].atom);
+    }
+
+    static void skipWhitespaceAndComments(const std::string& source, size_t& pos) {
+        while (pos < source.size()) {
+            if (isWhitespace(source[pos])) {
+                ++pos;
+                continue;
+            }
+            if (source[pos] == ';') {
+                while (pos < source.size() && source[pos] != '\n') ++pos;
+                continue;
+            }
+            break;
+        }
+    }
+
+    static std::string parseStringToken(const std::string& source, size_t& pos,
+                                        std::vector<ParseDiagnostic>& diags) {
+        std::string out;
+        out.push_back('"');
+        ++pos;
+        bool escaped = false;
+        while (pos < source.size()) {
+            char c = source[pos++];
+            out.push_back(c);
+            if (escaped) {
+                escaped = false;
+                continue;
+            }
+            if (c == '\\') {
+                escaped = true;
+            } else if (c == '"') {
+                return out;
+            }
+        }
+        diags.push_back({1, 1, "Unterminated string in Scheme source", "error"});
+        return out;
+    }
+
+    static std::string parseAtomToken(const std::string& source, size_t& pos) {
+        size_t start = pos;
+        while (pos < source.size() && !isDelimiter(source[pos])) ++pos;
+        return source.substr(start, pos - start);
+    }
+
+    static SExpr makeQuotedForm(const SExpr& value) {
+        SExpr q;
+        q.isList = true;
+        SExpr quoteSym;
+        quoteSym.atom = "quote";
+        q.list.push_back(quoteSym);
+        q.list.push_back(value);
+        return q;
+    }
+
+    static SExpr parseSingleForm(const std::string& source, size_t& pos,
+                                 std::vector<ParseDiagnostic>& diags) {
+        skipWhitespaceAndComments(source, pos);
+        if (pos >= source.size()) return SExpr{};
+
+        if (source[pos] == '(') {
+            ++pos;
+            SExpr list;
+            list.isList = true;
+            for (;;) {
+                skipWhitespaceAndComments(source, pos);
+                if (pos >= source.size()) {
+                    diags.push_back({1, 1, "Unbalanced parentheses in Scheme source", "error"});
+                    return list;
+                }
+                if (source[pos] == ')') {
+                    ++pos;
+                    return list;
+                }
+                list.list.push_back(parseSingleForm(source, pos, diags));
+            }
+        }
+
+        if (source[pos] == ')') {
+            diags.push_back({1, 1, "Unmatched closing parenthesis in Scheme source", "error"});
+            ++pos;
+            return SExpr{};
+        }
+
+        if (source[pos] == '\'' || source[pos] == '`') {
+            ++pos;
+            SExpr inner = parseSingleForm(source, pos, diags);
+            return makeQuotedForm(inner);
+        }
+
+        if (source[pos] == '"') {
+            SExpr atom;
+            atom.atom = parseStringToken(source, pos, diags);
+            return atom;
+        }
+
+        SExpr atom;
+        atom.atom = parseAtomToken(source, pos);
+        return atom;
+    }
+
+    static std::vector<SExpr> parseForms(const std::string& source,
+                                         std::vector<ParseDiagnostic>& diags) {
+        std::vector<SExpr> out;
+        size_t pos = 0;
+        while (pos < source.size()) {
+            skipWhitespaceAndComments(source, pos);
+            if (pos >= source.size()) break;
+            out.push_back(parseSingleForm(source, pos, diags));
+        }
+        return out;
+    }
+
+    static void appendExpressionStatement(ASTNode* owner, const std::string& role, ASTNode* expr) {
+        if (!expr) return;
+        auto* stmt = new ExpressionStatement();
+        stmt->id = IdGenerator::next("exprstmt");
+        stmt->setChild("expression", expr);
+        owner->addChild(role, stmt);
+    }
+
+    static ASTNode* convertExpression(const SExpr& expr);
+
+    static ASTNode* convertIf(const SExpr& expr) {
+        if (expr.list.size() < 3) return nullptr;
+        auto* node = new IfStatement();
+        node->id = IdGenerator::next("if");
+        node->setChild("condition", convertExpression(expr.list[1]));
+        appendExpressionStatement(node, "thenBranch", convertExpression(expr.list[2]));
+        if (expr.list.size() > 3) {
+            appendExpressionStatement(node, "elseBranch", convertExpression(expr.list[3]));
+        }
+        return node;
+    }
+
+    static ASTNode* convertCond(const SExpr& expr) {
+        IfStatement* root = nullptr;
+        IfStatement* cur = nullptr;
+        for (size_t i = 1; i < expr.list.size(); ++i) {
+            const auto& clause = expr.list[i];
+            if (!clause.isList || clause.list.empty()) continue;
+            auto* node = new IfStatement();
+            node->id = IdGenerator::next("if");
+            node->setChild("condition", convertExpression(clause.list[0]));
+            if (clause.list.size() > 1) {
+                appendExpressionStatement(node, "thenBranch", convertExpression(clause.list[1]));
+            }
+            if (!root) root = node;
+            if (cur) cur->addChild("elseBranch", node);
+            cur = node;
+        }
+        return root;
+    }
+
+    static ASTNode* convertLambda(const SExpr& expr) {
+        auto* lambda = new LambdaExpression();
+        lambda->id = IdGenerator::next("lambda");
+        if (expr.list.size() > 1 && expr.list[1].isList) {
+            for (const auto& p : expr.list[1].list) {
+                if (p.isList || p.atom.empty()) continue;
+                auto* param = new Parameter(IdGenerator::next("param"), p.atom);
+                lambda->addChild("parameters", param);
+            }
+        }
+        for (size_t i = 2; i < expr.list.size(); ++i) {
+            appendExpressionStatement(lambda, "body", convertExpression(expr.list[i]));
+        }
+        return lambda;
+    }
+
+    static ASTNode* convertLet(const SExpr& expr) {
+        auto* block = new Block();
+        block->id = IdGenerator::next("blk");
+        if (expr.list.size() > 1 && expr.list[1].isList) {
+            for (const auto& binding : expr.list[1].list) {
+                if (!binding.isList || binding.list.empty()) continue;
+                std::string name = atomText(binding.list[0]);
+                if (name.empty()) continue;
+                auto* v = new Variable(IdGenerator::next("var"), name);
+                if (binding.list.size() > 1) {
+                    v->setChild("value", convertExpression(binding.list[1]));
+                }
+                block->addChild("statements", v);
+            }
+        }
+        for (size_t i = 2; i < expr.list.size(); ++i) {
+            appendExpressionStatement(block, "statements", convertExpression(expr.list[i]));
+        }
+        return block;
+    }
+
+    static ASTNode* convertDo(const SExpr& expr) {
+        auto* loop = new ForLoop();
+        loop->id = IdGenerator::next("for");
+        loop->iteratorName = "do";
+
+        if (expr.list.size() > 1 && expr.list[1].isList && !expr.list[1].list.empty()) {
+            const auto& firstBinding = expr.list[1].list[0];
+            if (firstBinding.isList && !firstBinding.list.empty()) {
+                loop->iteratorName = atomText(firstBinding.list[0]);
+                if (firstBinding.list.size() > 1) {
+                    loop->setChild("iterable", convertExpression(firstBinding.list[1]));
+                }
+            }
+        }
+
+        size_t bodyStart = 3;
+        if (expr.list.size() > 2 && expr.list[2].isList && expr.list[2].list.size() > 1) {
+            appendExpressionStatement(loop, "body", convertExpression(expr.list[2].list[1]));
+        }
+        for (size_t i = bodyStart; i < expr.list.size(); ++i) {
+            appendExpressionStatement(loop, "body", convertExpression(expr.list[i]));
+        }
+        return loop;
+    }
+
+    static ASTNode* convertBegin(const SExpr& expr) {
+        auto* block = new Block();
+        block->id = IdGenerator::next("blk");
+        for (size_t i = 1; i < expr.list.size(); ++i) {
+            appendExpressionStatement(block, "statements", convertExpression(expr.list[i]));
+        }
+        return block;
+    }
+
+    static ASTNode* convertCall(const SExpr& expr) {
+        auto* call = new FunctionCall();
+        call->id = IdGenerator::next("call");
+
+        std::string head = headSymbol(expr);
+        if (head == "call-with-current-continuation" || head == "call/cc") {
+            call->functionName = head;
+            auto* exec = new ExecAnnotation();
+            exec->id = IdGenerator::next("anno");
+            exec->mode = "continuation";
+            call->addChild("annotations", exec);
+        } else {
+            call->functionName = atomText(expr.list[0]);
+        }
+
+        size_t start = 1;
+        for (size_t i = start; i < expr.list.size(); ++i) {
+            ASTNode* arg = convertExpression(expr.list[i]);
+            if (arg) call->addChild("arguments", arg);
+        }
+        return call;
+    }
+
+    static ASTNode* convertValues(const SExpr& expr) {
+        auto* call = new FunctionCall();
+        call->id = IdGenerator::next("call");
+        call->functionName = "values";
+        for (size_t i = 1; i < expr.list.size(); ++i) {
+            ASTNode* arg = convertExpression(expr.list[i]);
+            if (arg) call->addChild("arguments", arg);
+        }
+
+        auto* contract = new ContractAnnotation();
+        contract->id = IdGenerator::next("anno");
+        contract->returnShape = "multiple-values";
+        call->addChild("annotations", contract);
+        return call;
+    }
+
+    static ASTNode* convertQuote(const SExpr& expr) {
+        ASTNode* quoted = (expr.list.size() > 1) ? convertExpression(expr.list[1]) : nullptr;
+        if (!quoted) quoted = new VariableReference(IdGenerator::next("ref"), "nil");
+        auto* meta = new MetaAnnotation();
+        meta->id = IdGenerator::next("anno");
+        meta->state = "quoted";
+        quoted->addChild("annotations", meta);
+        return quoted;
+    }
+
+    static void convertDefineFunction(const SExpr& form, Module* module) {
+        if (form.list.size() < 3 || !form.list[1].isList || form.list[1].list.empty()) return;
+        std::string name = atomText(form.list[1].list[0]);
+        auto* fn = new Function(IdGenerator::next("fn"), name);
+
+        for (size_t i = 1; i < form.list[1].list.size(); ++i) {
+            std::string pname = atomText(form.list[1].list[i]);
+            if (pname.empty()) continue;
+            fn->addChild("parameters", new Parameter(IdGenerator::next("param"), pname));
+        }
+
+        for (size_t i = 2; i < form.list.size(); ++i) {
+            appendExpressionStatement(fn, "body", convertExpression(form.list[i]));
+        }
+        module->addChild("functions", fn);
+    }
+
+    static void convertDefineVariable(const SExpr& form, Module* module) {
+        if (form.list.size() < 2) return;
+        std::string name = atomText(form.list[1]);
+        auto* var = new Variable(IdGenerator::next("var"), name);
+        if (form.list.size() > 2) {
+            var->setChild("value", convertExpression(form.list[2]));
+        }
+        module->addChild("variables", var);
+    }
+
+    static void convertDefineSyntax(const SExpr& form, Module* module) {
+        if (form.list.size() < 2) return;
+        auto* macro = new MacroDefinition(IdGenerator::next("mac"), atomText(form.list[1]));
+        macro->isFunctionLike = true;
+        macro->body = "syntax-rules";
+
+        auto* meta = new MetaAnnotation();
+        meta->id = IdGenerator::next("anno");
+        meta->state = "hygienic";
+        macro->addChild("annotations", meta);
+
+        module->addChild("statements", macro);
+    }
+
+    static void convertTopLevelForm(const SExpr& form, Module* module) {
+        if (!form.isList || form.list.empty()) return;
+        std::string head = headSymbol(form);
+
+        if (head == "define") {
+            if (form.list.size() > 1 && form.list[1].isList) {
+                convertDefineFunction(form, module);
+            } else {
+                convertDefineVariable(form, module);
+            }
+            return;
+        }
+
+        if (head == "define-syntax") {
+            convertDefineSyntax(form, module);
+            return;
+        }
+
+        appendExpressionStatement(module, "statements", convertExpression(form));
+    }
+};
+
+inline ASTNode* SchemeParser::convertExpression(const SExpr& expr) {
+    if (!expr.isList) {
+        if (expr.atom.empty()) return nullptr;
+        if (isInteger(expr.atom)) return new IntegerLiteral(IdGenerator::next("int"), std::stoi(expr.atom));
+        if (isFloat(expr.atom)) return new FloatLiteral(IdGenerator::next("flt"), expr.atom);
+        if (isStringToken(expr.atom)) {
+            return new StringLiteral(IdGenerator::next("str"), expr.atom.substr(1, expr.atom.size() - 2));
+        }
+        if (expr.atom == "#t" || expr.atom == "t") return new BooleanLiteral(IdGenerator::next("bool"), true);
+        if (expr.atom == "#f" || expr.atom == "nil") return new BooleanLiteral(IdGenerator::next("bool"), false);
+        return new VariableReference(IdGenerator::next("ref"), expr.atom);
+    }
+
+    std::string head = headSymbol(expr);
+    if (head == "if") return convertIf(expr);
+    if (head == "cond") return convertCond(expr);
+    if (head == "lambda") return convertLambda(expr);
+    if (head == "let" || head == "let*" || head == "letrec") return convertLet(expr);
+    if (head == "do") return convertDo(expr);
+    if (head == "begin") return convertBegin(expr);
+    if (head == "values") return convertValues(expr);
+    if (head == "quote") return convertQuote(expr);
+    return convertCall(expr);
+}

editor/tests/step374_test.cpp

@@ -0,0 +1,208 @@
+// Step 374: Scheme Parser (12 tests)
+
+#include <cassert>
+#include <iostream>
+#include <string>
+#include "Pipeline.h"
+#include "ast/SchemeParser.h"
+
+static bool hasBodyNode(const Function* fn, const std::string& conceptType) {
+    for (auto* stmt : fn->getChildren("body")) {
+        if (stmt->conceptType == conceptType) return true;
+        if (stmt->conceptType == "ExpressionStatement") {
+            ASTNode* expr = stmt->getChild("expression");
+            if (expr && expr->conceptType == conceptType) return true;
+        }
+    }
+    return false;
+}
+
+int main() {
+    int passed = 0;
+
+    // Test 1: define function parsing
+    {
+        auto mod = SchemeParser::parseScheme("(define (add x y) (+ x y))");
+        assert(mod->targetLanguage == "scheme");
+        assert(mod->getChildren("functions").size() == 1);
+        auto* fn = static_cast<Function*>(mod->getChildren("functions")[0]);
+        assert(fn->name == "add");
+        assert(fn->getChildren("parameters").size() == 2);
+        std::cout << "Test 1 PASSED: define function parsing\n";
+        passed++;
+    }
+
+    // Test 2: define variable parsing
+    {
+        auto mod = SchemeParser::parseScheme("(define answer 42)");
+        assert(mod->getChildren("variables").size() == 1);
+        auto* var = static_cast<Variable*>(mod->getChildren("variables")[0]);
+        assert(var->name == "answer");
+        assert(var->getChild("value") != nullptr);
+        std::cout << "Test 2 PASSED: define variable parsing\n";
+        passed++;
+    }
+
+    // Test 3: lambda parsing
+    {
+        auto mod = SchemeParser::parseScheme("(define (mk) (lambda (x) (+ x 1)))");
+        auto* fn = static_cast<Function*>(mod->getChildren("functions")[0]);
+        assert(hasBodyNode(fn, "LambdaExpression"));
+        std::cout << "Test 3 PASSED: lambda parsing\n";
+        passed++;
+    }
+
+    // Test 4: let / let* / letrec parsing
+    {
+        std::string src =
+            "(define (a) (let ((x 1)) x))\n"
+            "(define (b) (let* ((x 1) (y 2)) (+ x y)))\n"
+            "(define (c) (letrec ((f (lambda (n) n))) (f 1)))";
+        auto mod = SchemeParser::parseScheme(src);
+        auto* fa = static_cast<Function*>(mod->getChildren("functions")[0]);
+        auto* fb = static_cast<Function*>(mod->getChildren("functions")[1]);
+        auto* fc = static_cast<Function*>(mod->getChildren("functions")[2]);
+        assert(hasBodyNode(fa, "Block"));
+        assert(hasBodyNode(fb, "Block"));
+        assert(hasBodyNode(fc, "Block"));
+        std::cout << "Test 4 PASSED: let variants parsing\n";
+        passed++;
+    }
+
+    // Test 5: if and cond parsing
+    {
+        std::string src =
+            "(define (s x) (if x 1 0))\n"
+            "(define (c x) (cond ((> x 0) 1) ((< x 0) -1) (else 0)))";
+        auto mod = SchemeParser::parseScheme(src);
+        auto* f1 = static_cast<Function*>(mod->getChildren("functions")[0]);
+        auto* f2 = static_cast<Function*>(mod->getChildren("functions")[1]);
+        assert(hasBodyNode(f1, "IfStatement"));
+        assert(hasBodyNode(f2, "IfStatement"));
+        std::cout << "Test 5 PASSED: if/cond parsing\n";
+        passed++;
+    }
+
+    // Test 6: do loop parsing
+    {
+        std::string src = "(define (loopn n) (do ((i 0 (+ i 1))) ((> i n) i) (display i)))";
+        auto mod = SchemeParser::parseScheme(src);
+        auto* fn = static_cast<Function*>(mod->getChildren("functions")[0]);
+        assert(hasBodyNode(fn, "ForLoop"));
+        std::cout << "Test 6 PASSED: do loop parsing\n";
+        passed++;
+    }
+
+    // Test 7: call/cc continuation annotation
+    {
+        std::string src =
+            "(define (cc f) (call-with-current-continuation f))\n"
+            "(define (cc2 f) (call/cc f))";
+        auto mod = SchemeParser::parseScheme(src);
+        auto* fn = static_cast<Function*>(mod->getChildren("functions")[0]);
+        bool hasContinuation = false;
+        for (auto* stmt : fn->getChildren("body")) {
+            ASTNode* expr = stmt->getChild("expression");
+            if (!expr || expr->conceptType != "FunctionCall") continue;
+            for (auto* anno : expr->getChildren("annotations")) {
+                if (anno->conceptType == "ExecAnnotation") {
+                    auto* ex = static_cast<ExecAnnotation*>(anno);
+                    if (ex->mode == "continuation") hasContinuation = true;
+                }
+            }
+        }
+        assert(hasContinuation);
+        std::cout << "Test 7 PASSED: call/cc continuation annotation\n";
+        passed++;
+    }
+
+    // Test 8: define-syntax -> macro + hygienic meta
+    {
+        std::string src = "(define-syntax when1 (syntax-rules () ((_ t b) (if t b #f))))";
+        auto mod = SchemeParser::parseScheme(src);
+        bool foundMacro = false;
+        bool hygienic = false;
+        for (auto* stmt : mod->getChildren("statements")) {
+            if (stmt->conceptType != "MacroDefinition") continue;
+            foundMacro = true;
+            for (auto* anno : stmt->getChildren("annotations")) {
+                if (anno->conceptType == "MetaAnnotation") {
+                    auto* m = static_cast<MetaAnnotation*>(anno);
+                    if (m->state == "hygienic") hygienic = true;
+                }
+            }
+        }
+        assert(foundMacro && hygienic);
+        std::cout << "Test 8 PASSED: define-syntax hygienic macro mapping\n";
+        passed++;
+    }
+
+    // Test 9: values multi-return mapping
+    {
+        std::string src = "(define (pair x) (values x (+ x 1)))";
+        auto mod = SchemeParser::parseScheme(src);
+        auto* fn = static_cast<Function*>(mod->getChildren("functions")[0]);
+        bool hasContract = false;
+        for (auto* stmt : fn->getChildren("body")) {
+            ASTNode* expr = stmt->getChild("expression");
+            if (!expr || expr->conceptType != "FunctionCall") continue;
+            for (auto* anno : expr->getChildren("annotations")) {
+                if (anno->conceptType == "ContractAnnotation") hasContract = true;
+            }
+        }
+        assert(hasContract);
+        std::cout << "Test 9 PASSED: values -> Contract annotation\n";
+        passed++;
+    }
+
+    // Test 10: begin form maps to sequence block
+    {
+        std::string src = "(define (f) (begin (display 1) (display 2) 3))";
+        auto mod = SchemeParser::parseScheme(src);
+        auto* fn = static_cast<Function*>(mod->getChildren("functions")[0]);
+        assert(hasBodyNode(fn, "Block"));
+        std::cout << "Test 10 PASSED: begin -> block sequence\n";
+        passed++;
+    }
+
+    // Test 11: deep nested s-expressions
+    {
+        std::string src = "(define (deep x) (a (b (c (d (e (f (g x))))))))";
+        auto mod = SchemeParser::parseScheme(src);
+        auto* fn = static_cast<Function*>(mod->getChildren("functions")[0]);
+        assert(hasBodyNode(fn, "FunctionCall"));
+        std::cout << "Test 11 PASSED: deep nesting parse\n";
+        passed++;
+    }
+
+    // Test 12: mixed source + pipeline route + diagnostics
+    {
+        std::string src =
+            "(define x 1)\n"
+            "(define (id y) y)\n"
+            "(define-syntax m (syntax-rules () ((_ z) z)))\n";
+        auto mod = SchemeParser::parseScheme(src);
+        assert(mod->getChildren("variables").size() == 1);
+        assert(mod->getChildren("functions").size() == 1);
+        bool macroFound = false;
+        for (auto* stmt : mod->getChildren("statements")) {
+            if (stmt->conceptType == "MacroDefinition") macroFound = true;
+        }
+        assert(macroFound);
+
+        Pipeline p;
+        std::vector<ParseDiagnostic> diags;
+        auto parsedScheme = p.parse("(define (f x) x)", "scheme", diags);
+        auto parsedScm = p.parse("(define (f x) x)", "scm", diags);
+        assert(parsedScheme != nullptr && parsedScm != nullptr);
+
+        auto malformed = SchemeParser::parseSchemeWithDiagnostics("(define (f x) (+ x 1)");
+        assert(!malformed.diagnostics.empty());
+        std::cout << "Test 12 PASSED: mixed forms + pipeline route + diagnostics\n";
+        passed++;
+    }
+
+    std::cout << "\nResults: " << passed << "/12\n";
+    assert(passed == 12);
+    return 0;
+}

progress.md

@@ -2565,6 +2565,52 @@ artifact compatibility with Semanno and compact AST tooling.
 - `editor/tests/step373_test.cpp` remains within project file-size guidance
   for test artifacts (`147` lines)
 
+### Step 374: Scheme Parser
+**Status:** PASS (12/12 tests)
+
+Added a dedicated Scheme parser with S-expression parsing and Scheme-specific
+form mapping into the Whetstone AST, including continuation and hygienic macro
+signals.
+
+**Files created:**
+- `editor/src/ast/SchemeParser.h` — Scheme parse support:
+  - recursive S-expression reader with Scheme comment and quote handling
+  - top-level mapping for `define` (function/value) and `define-syntax`
+  - expression mapping for `lambda`, `let`/`let*`/`letrec`, `if`, `cond`,
+    `do`, `begin`, `call-with-current-continuation`/`call/cc`, `quote`,
+    and `values`
+  - continuation call mapping with `Exec(mode=continuation)` annotation
+  - `define-syntax` mapping to `MacroDefinition` with hygienic `Meta` signal
+- `editor/tests/step374_test.cpp` — 12 tests covering:
+  1. `define` function parsing
+  2. `define` variable parsing
+  3. `lambda` parsing
+  4. `let` variants mapping
+  5. `if`/`cond` mapping
+  6. `do` loop mapping
+  7. `call/cc` continuation annotation mapping
+  8. `define-syntax` hygienic macro mapping
+  9. `values` contract mapping
+  10. `begin` sequence mapping
+  11. deep nesting parsing
+  12. mixed forms + pipeline scheme/scm routing + malformed diagnostics
+
+**Files modified:**
+- `editor/src/ast/Parser.h` — include `ast/SchemeParser.h`
+- `editor/src/Pipeline.h` — add parse routing for `\"scheme\"` and `\"scm\"`
+- `editor/CMakeLists.txt` — `step374_test` target
+
+**Verification run:**
+- `step374_test` — PASS (12/12) new step coverage
+- `step373_test` — PASS (8/8) regression coverage
+- `step372_test` — PASS (12/12) regression coverage
+- `step371_test` — PASS (12/12) regression coverage
+- `step370_test` — PASS (12/12) regression coverage
+
+**Architecture gate check:**
+- `editor/src/ast/SchemeParser.h` is within header size limit
+  (`461` lines <= `600`)
+
 # Roadmap Planning — Sprints 12-25+
 
 ## Status: Planning Complete (Sprints 12-19 detailed, 20-25 in roadmap.md)