X-Git-Url: https://git.saurik.com/cycript.git/blobdiff_plain/127c1a9c2cef616211a88e16343614fee9f3b664..dbf9d389223676006c85201505a5989adc04c978:/Replace.cpp

diff --git a/Replace.cpp b/Replace.cpp
index 9a27171..b658cf7 100644
--- a/Replace.cpp
+++ b/Replace.cpp
@@ -1,20 +1,20 @@
 /* Cycript - Optimizing JavaScript Compiler/Runtime
- * Copyright (C) 2009-2010  Jay Freeman (saurik)
+ * Copyright (C) 2009-2013  Jay Freeman (saurik)
 */
 
-/* GNU Lesser General Public License, Version 3 {{{ */
+/* GNU General Public License, Version 3 {{{ */
 /*
- * Cycript is free software: you can redistribute it and/or modify it under
- * the terms of the GNU Lesser General Public License as published by the
- * Free Software Foundation, either version 3 of the License, or (at your
- * option) any later version.
+ * Cycript is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published
+ * by the Free Software Foundation, either version 3 of the License,
+ * or (at your option) any later version.
  *
- * Cycript is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
- * License for more details.
+ * Cycript is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
  *
- * You should have received a copy of the GNU Lesser General Public License
+ * You should have received a copy of the GNU General Public License
  * along with Cycript.  If not, see <http://www.gnu.org/licenses/>.
 **/
 /* }}} */
@@ -24,22 +24,24 @@
 
 #include <iomanip>
 
+CYFunctionExpression *CYNonLocalize(CYContext &context, CYFunctionExpression *function) {
+    function->nonlocal_ = context.nextlocal_;
+    return function;
+}
+
 CYExpression *CYAdd::Replace(CYContext &context) {
     CYInfix::Replace(context);
 
-    CYExpression *lhp(lhs_->Primitive(context));
-    CYExpression *rhp(rhs_->Primitive(context));
-
-    CYString *lhs(dynamic_cast<CYString *>(lhp));
-    CYString *rhs(dynamic_cast<CYString *>(rhp));
+    CYString *lhs(dynamic_cast<CYString *>(lhs_));
+    CYString *rhs(dynamic_cast<CYString *>(rhs_));
 
     if (lhs != NULL || rhs != NULL) {
         if (lhs == NULL) {
-            lhs = lhp->String(context);
+            lhs = lhs_->String(context);
             if (lhs == NULL)
                 return this;
         } else if (rhs == NULL) {
-            rhs = rhp->String(context);
+            rhs = rhs_->String(context);
             if (rhs == NULL)
                 return this;
         }
@@ -47,21 +49,29 @@ CYExpression *CYAdd::Replace(CYContext &context) {
         return lhs->Concat(context, rhs);
     }
 
-    if (CYNumber *lhn = lhp->Number(context))
-        if (CYNumber *rhn = rhp->Number(context))
+    if (CYNumber *lhn = lhs_->Number(context))
+        if (CYNumber *rhn = rhs_->Number(context))
             return $D(lhn->Value() + rhn->Value());
 
     return this;
 }
 
 CYExpression *CYAddressOf::Replace(CYContext &context) {
-    CYPrefix::Replace(context);
     return $C0($M(rhs_, $S("$cya")));
 }
 
-void CYArgument::Replace(CYContext &context) { $T()
+CYArgument *CYArgument::Replace(CYContext &context) { $T(NULL)
     context.Replace(value_);
-    next_->Replace(context);
+    next_ = next_->Replace(context);
+
+    if (value_ == NULL) {
+        if (next_ == NULL)
+            return NULL;
+        else
+            value_ = $U;
+    }
+
+    return this;
 }
 
 CYExpression *CYArray::Replace(CYContext &context) {
@@ -72,7 +82,7 @@ CYExpression *CYArray::Replace(CYContext &context) {
 CYExpression *CYArrayComprehension::Replace(CYContext &context) {
     CYVariable *cyv($V("$cyv"));
 
-    return $C0($F(NULL, $P1("$cyv", comprehensions_->Parameters(context)), $$->*
+    return $C0($F(NULL, $P1($L("$cyv"), comprehensions_->Parameters(context)), $$->*
         $E($ CYAssign(cyv, $ CYArray()))->*
         comprehensions_->Replace(context, $E($C1($M(cyv, $S("push")), expression_)))->*
         $ CYReturn(cyv)
@@ -114,7 +124,7 @@ namespace cy {
 namespace Syntax {
 
 void Catch::Replace(CYContext &context) { $T()
-    CYScope scope(CYScopeCatch, context, code_.statements_);
+    CYScope scope(true, context, code_.statements_);
 
     context.Replace(name_);
     context.scope_->Declare(context, name_, CYIdentifierCatch);
@@ -136,12 +146,29 @@ CYStatement *CYComment::Replace(CYContext &context) {
 }
 
 CYExpression *CYCompound::Replace(CYContext &context) {
-    context.ReplaceAll(expressions_);
-    if (expressions_ == NULL)
-        return NULL;
+    if (next_ == NULL)
+        return expression_;
+
+    context.Replace(expression_);
+    context.Replace(next_);
+
+    if (CYCompound *compound = dynamic_cast<CYCompound *>(expression_)) {
+        expression_ = compound->expression_;
+        compound->expression_ = compound->next_;
+        compound->next_ = next_;
+        next_ = compound;
+    }
+
     return this;
 }
 
+CYExpression *CYCompound::Primitive(CYContext &context) {
+    CYExpression *expression(expression_);
+    if (expression == NULL || next_ != NULL)
+        return NULL;
+    return expression->Primitive(context);
+}
+
 CYFunctionParameter *CYComprehension::Parameters(CYContext &context) const { $T(NULL)
     CYFunctionParameter *next(next_->Parameters(context));
     if (CYFunctionParameter *parameter = Parameter(context)) {
@@ -170,7 +197,7 @@ void CYContext::NonLocal(CYStatement *&statements) {
         CYIdentifier *unique(nextlocal_->identifier_->Replace(context));
 
         CYStatement *declare(
-            $ CYVar($L1($L(unique, $ CYObject()))));
+            $ CYVar($L1($ CYDeclaration(unique, $ CYObject()))));
 
         cy::Syntax::Catch *rescue(
             $ cy::Syntax::Catch(cye, $$->*
@@ -188,13 +215,17 @@ void CYContext::NonLocal(CYStatement *&statements) {
 }
 
 CYIdentifier *CYContext::Unique() {
-    return $ CYIdentifier(apr_psprintf($pool, "$cy%u", unique_++));
+    return $ CYIdentifier($pool.strcat("$cy", $pool.itoa(unique_++), NULL));
 }
 
 CYStatement *CYContinue::Replace(CYContext &context) {
     return this;
 }
 
+CYStatement *CYDebugger::Replace(CYContext &context) {
+    return this;
+}
+
 CYAssignment *CYDeclaration::Assignment(CYContext &context) {
     if (initialiser_ == NULL)
         return NULL;
@@ -209,7 +240,7 @@ CYVariable *CYDeclaration::Variable(CYContext &context) {
 }
 
 CYStatement *CYDeclaration::ForEachIn(CYContext &context, CYExpression *value) {
-    return $ CYVar($L1($L(identifier_, value)));
+    return $ CYVar($L1($ CYDeclaration(identifier_, value)));
 }
 
 CYExpression *CYDeclaration::Replace(CYContext &context) {
@@ -224,26 +255,27 @@ void CYDeclarations::Replace(CYContext &context) { $T()
 }
 
 CYProperty *CYDeclarations::Property(CYContext &context) { $T(NULL)
-    return $ CYProperty(declaration_->identifier_, declaration_->initialiser_ ?: $U, next_->Property(context));
+    return $ CYProperty(declaration_->identifier_, declaration_->initialiser_, next_->Property(context));
 }
 
 CYFunctionParameter *CYDeclarations::Parameter(CYContext &context) { $T(NULL)
-    return $ CYFunctionParameter(declaration_->identifier_, next_->Parameter(context));
+    return $ CYFunctionParameter($ CYDeclaration(declaration_->identifier_), next_->Parameter(context));
 }
 
 CYArgument *CYDeclarations::Argument(CYContext &context) { $T(NULL)
-    return $ CYArgument(declaration_->initialiser_ ?: $U, next_->Argument(context));
+    return $ CYArgument(declaration_->initialiser_, next_->Argument(context));
 }
 
 CYCompound *CYDeclarations::Compound(CYContext &context) { $T(NULL)
-    CYCompound *compound(next_->Compound(context) ?: $ CYCompound());
+    CYCompound *compound(next_->Compound(context));
     if (CYAssignment *assignment = declaration_->Assignment(context))
-        compound->AddPrev(assignment);
+        compound = $ CYCompound(assignment, compound);
     return compound;
 }
 
 CYExpression *CYDirectMember::Replace(CYContext &context) {
-    Replace_(context);
+    context.Replace(object_);
+    context.Replace(property_);
     return this;
 }
 
@@ -262,13 +294,13 @@ CYStatement *CYEmpty::Replace(CYContext &context) {
     return NULL;
 }
 
+CYExpression *CYEncodedType::Replace(CYContext &context) {
+    return typed_->Replace(context);
+}
+
 CYStatement *CYExpress::Replace(CYContext &context) {
     while (CYExpress *express = dynamic_cast<CYExpress *>(next_)) {
-        CYCompound *compound(dynamic_cast<CYCompound *>(express->expression_));
-        if (compound == NULL)
-            compound = $ CYCompound(express->expression_);
-        compound->AddPrev(expression_);
-        expression_ = compound;
+        expression_ = $ CYCompound(expression_, express->expression_);
         SetNext(express->next_);
     }
 
@@ -303,6 +335,12 @@ CYString *CYFalse::String(CYContext &context) {
     return $S("false");
 }
 
+CYExpression *CYFatArrow::Replace(CYContext &context) {
+    CYFunctionExpression *function($ CYFunctionExpression(NULL, parameters_, code_));
+    function->this_.SetNext(context.this_);
+    return function;
+}
+
 void CYFinally::Replace(CYContext &context) { $T()
     code_.Replace(context);
 }
@@ -335,17 +373,23 @@ CYStatement *CYForIn::Replace(CYContext &context) {
 }
 
 CYFunctionParameter *CYForInComprehension::Parameter(CYContext &context) const {
-    return $ CYFunctionParameter(name_);
+    return $ CYFunctionParameter($ CYDeclaration(name_));
 }
 
 CYStatement *CYForInComprehension::Replace(CYContext &context, CYStatement *statement) const {
     return $ CYForIn($V(name_), set_, CYComprehension::Replace(context, statement));
 }
 
-CYStatement *CYForEachIn::Replace(CYContext &context) {
+CYStatement *CYForOf::Replace(CYContext &context) {
+    if (CYAssignment *assignment = initialiser_->Assignment(context))
+        return $ CYBlock($$->*
+            $E(assignment)->*
+            this
+        );
+
     CYIdentifier *cys($I("$cys")), *cyt($I("$cyt"));
 
-    return $ CYLet($L2($L(cys, set_), $L(cyt)), $$->*
+    return $ CYLetStatement($L2($ CYDeclaration(cys, set_), $ CYDeclaration(cyt)), $$->*
         $ CYForIn($V(cyt), $V(cys), $ CYBlock($$->*
             initialiser_->ForEachIn(context, $M($V(cys), $V(cyt)))->*
             code_
@@ -353,14 +397,14 @@ CYStatement *CYForEachIn::Replace(CYContext &context) {
     );
 }
 
-CYFunctionParameter *CYForEachInComprehension::Parameter(CYContext &context) const {
-    return $ CYFunctionParameter(name_);
+CYFunctionParameter *CYForOfComprehension::Parameter(CYContext &context) const {
+    return $ CYFunctionParameter($ CYDeclaration(name_));
 }
 
-CYStatement *CYForEachInComprehension::Replace(CYContext &context, CYStatement *statement) const {
+CYStatement *CYForOfComprehension::Replace(CYContext &context, CYStatement *statement) const {
     CYIdentifier *cys($I("cys"));
 
-    return $E($C0($F(NULL, $P1("$cys"), $$->*
+    return $E($C0($F(NULL, $P1($L("$cys")), $$->*
         $E($ CYAssign($V(cys), set_))->*
         $ CYForIn($V(name_), $V(cys), $ CYBlock($$->*
             $E($ CYAssign($V(name_), $M($V(cys), $V(name_))))->*
@@ -378,7 +422,8 @@ void CYFunction::Replace_(CYContext &context, bool outer) {
     if (outer)
         Inject(context);
 
-    CYScope scope(CYScopeFunction, context, code_.statements_);
+    CYThisScope *_this(context.this_);
+    context.this_ = CYGetLast(&this_);
 
     CYNonLocal *nonlocal(context.nonlocal_);
     CYNonLocal *nextlocal(context.nextlocal_);
@@ -393,20 +438,27 @@ void CYFunction::Replace_(CYContext &context, bool outer) {
         context.nextlocal_ = nonlocal_;
     }
 
+    CYScope scope(!localize, context, code_.statements_);
+
     if (!outer && name_ != NULL)
         Inject(context);
 
-    if (parameters_ != NULL)
-        parameters_ = parameters_->Replace(context, code_);
-
+    parameters_->Replace(context, code_);
     code_.Replace(context);
 
+    if (CYIdentifier *identifier = this_.identifier_)
+        code_.statements_ = $$->*
+            $ CYVar($L1($ CYDeclaration(identifier, $ CYThis())))->*
+            code_.statements_;
+
     if (localize)
         context.NonLocal(code_.statements_);
 
     context.nextlocal_ = nextlocal;
     context.nonlocal_ = nonlocal;
 
+    context.this_ = _this;
+
     scope.Close();
 }
 
@@ -415,12 +467,17 @@ CYExpression *CYFunctionExpression::Replace(CYContext &context) {
     return this;
 }
 
-CYFunctionParameter *CYFunctionParameter::Replace(CYContext &context, CYBlock &code) {
-    context.Replace(name_);
-    context.scope_->Declare(context, name_, CYIdentifierArgument);
-    if (next_ != NULL)
-        next_ = next_->Replace(context, code);
-    return this;
+void CYFunctionParameter::Replace(CYContext &context, CYBlock &code) { $T()
+    CYAssignment *assignment(initialiser_->Assignment(context));
+    context.Replace(initialiser_);
+
+    next_->Replace(context, code);
+
+    if (assignment != NULL)
+        // XXX: this cast is quite incorrect
+        code.AddPrev($ CYIf($ CYIdentical($ CYTypeOf(dynamic_cast<CYExpression *>(initialiser_)), $S("undefined")), $$->*
+            $E(assignment)
+        ));
 }
 
 CYStatement *CYFunctionStatement::Replace(CYContext &context) {
@@ -451,12 +508,10 @@ CYStatement *CYIfComprehension::Replace(CYContext &context, CYStatement *stateme
 }
 
 CYExpression *CYIndirect::Replace(CYContext &context) {
-    CYPrefix::Replace(context);
     return $M(rhs_, $S("$cyi"));
 }
 
 CYExpression *CYIndirectMember::Replace(CYContext &context) {
-    Replace_(context);
     return $M($ CYIndirect(object_), property_);
 }
 
@@ -471,21 +526,29 @@ CYStatement *CYLabel::Replace(CYContext &context) {
     return this;
 }
 
-CYStatement *CYLet::Replace(CYContext &context) {
-    declarations_->Replace(context);
-    return $ CYWith($ CYObject(declarations_->Property(context)), code_);
+CYExpression *CYLambda::Replace(CYContext &context) {
+    return $N2($V("Functor"), $ CYFunctionExpression(NULL, parameters_->Parameters(context), statements_), parameters_->TypeSignature(context, typed_->Replace(context)));
 }
 
-void CYMember::Replace_(CYContext &context) {
-    context.Replace(object_);
-    context.Replace(property_);
+CYStatement *CYLetStatement::Replace(CYContext &context) {
+    return $E($ CYCall(CYNonLocalize(context, $ CYFunctionExpression(NULL, declarations_->Parameter(context), code_)), declarations_->Argument(context)));
+}
+
+CYExpression *CYMultiply::Replace(CYContext &context) {
+    CYInfix::Replace(context);
+
+    if (CYNumber *lhn = lhs_->Number(context))
+        if (CYNumber *rhn = rhs_->Number(context))
+            return $D(lhn->Value() * rhn->Value());
+
+    return this;
 }
 
 namespace cy {
 namespace Syntax {
 
 CYExpression *New::AddArgument(CYContext &context, CYExpression *value) {
-    CYSetLast(arguments_, $ CYArgument(value));
+    CYSetLast(arguments_) = $ CYArgument(value);
     return this;
 }
 
@@ -511,7 +574,7 @@ CYNumber *CYNumber::Number(CYContext &context) {
 
 CYString *CYNumber::String(CYContext &context) {
     // XXX: there is a precise algorithm for this
-    return $S(apr_psprintf($pool, "%.17g", Value()));
+    return $S($pool.sprintf(24, "%.17g", Value()));
 }
 
 CYExpression *CYObject::Replace(CYContext &context) {
@@ -519,19 +582,6 @@ CYExpression *CYObject::Replace(CYContext &context) {
     return this;
 }
 
-CYFunctionParameter *CYOptionalFunctionParameter::Replace(CYContext &context, CYBlock &code) {
-    CYFunctionParameter *parameter($ CYFunctionParameter(name_, next_));
-    parameter = parameter->Replace(context, code);
-    context.Replace(initializer_);
-
-    CYVariable *name($V(name_));
-    code.AddPrev($ CYIf($ CYIdentical($ CYTypeOf(name), $S("undefined")), $$->*
-        $E($ CYAssign(name, initializer_))
-    ));
-
-    return parameter;
-}
-
 CYExpression *CYPostfix::Replace(CYContext &context) {
     context.Replace(lhs_);
     return this;
@@ -561,7 +611,7 @@ namespace {
 }
 
 void CYProgram::Replace(CYContext &context) {
-    CYScope scope(CYScopeProgram, context, statements_);
+    CYScope scope(true, context, statements_);
 
     context.nextlocal_ = $ CYNonLocal();
     context.ReplaceAll(statements_);
@@ -588,7 +638,7 @@ void CYProgram::Replace(CYContext &context) {
         const char *name;
 
         if (context.options_.verbose_)
-            name = apr_psprintf($pool, "$%"APR_SIZE_T_FMT"", offset);
+            name = $pool.strcat("$", $pool.itoa(offset), NULL);
         else {
             char id[8];
             id[7] = '\0';
@@ -607,7 +657,7 @@ void CYProgram::Replace(CYContext &context) {
                 goto id;
             }
 
-            name = apr_pstrmemdup($pool, id + position, 7 - position);
+            name = $pool.strmemdup(id + position, 7 - position);
             // XXX: at some point, this could become a keyword
         }
 
@@ -619,6 +669,8 @@ void CYProgram::Replace(CYContext &context) {
 void CYProperty::Replace(CYContext &context) { $T()
     context.Replace(value_);
     next_->Replace(context);
+    if (value_ == NULL)
+        value_ = $U;
 }
 
 CYStatement *CYReturn::Replace(CYContext &context) {
@@ -639,13 +691,11 @@ CYExpression *CYRubyBlock::Replace(CYContext &context) {
 }
 
 CYExpression *CYRubyProc::Replace(CYContext &context) {
-    CYFunctionExpression *function($ CYFunctionExpression(NULL, parameters_, code_));
-    function->nonlocal_ = context.nextlocal_;
-    return function;
+    return CYNonLocalize(context, $ CYFunctionExpression(NULL, parameters_, code_));
 }
 
-CYScope::CYScope(CYScopeType type, CYContext &context, CYStatement *&statements) :
-    type_(type),
+CYScope::CYScope(bool transparent, CYContext &context, CYStatement *&statements) :
+    transparent_(transparent),
     context_(context),
     statements_(statements),
     parent_(context.scope_)
@@ -662,10 +712,10 @@ void CYScope::Close() {
 }
 
 void CYScope::Declare(CYContext &context, CYIdentifier *identifier, CYIdentifierFlags flags) {
-    if (type_ == CYScopeCatch && flags != CYIdentifierCatch)
-        parent_->Declare(context, identifier, flags);
-    else
+    if (!transparent_ || flags == CYIdentifierArgument || flags == CYIdentifierCatch)
         internal_.insert(CYIdentifierAddressFlagsMap::value_type(identifier, flags));
+    else if (parent_ != NULL)
+        parent_->Declare(context, identifier, flags);
 }
 
 CYIdentifier *CYScope::Lookup(CYContext &context, CYIdentifier *identifier) {
@@ -791,6 +841,8 @@ CYStatement *CYSwitch::Replace(CYContext &context) {
 }
 
 CYExpression *CYThis::Replace(CYContext &context) {
+    if (context.this_ != NULL)
+        return $V(context.this_->Identifier(context));
     return this;
 }
 
@@ -828,9 +880,88 @@ CYStatement *Try::Replace(CYContext &context) {
 
 } }
 
+CYExpression *CYTypeArrayOf::Replace_(CYContext &context, CYExpression *type) {
+    return next_->Replace(context, $ CYCall($ CYDirectMember(type, $ CYString("arrayOf")), $ CYArgument(size_)));
+}
+
+CYExpression *CYTypeBlockWith::Replace_(CYContext &context, CYExpression *type) {
+    return next_->Replace(context, $ CYCall($ CYDirectMember(type, $ CYString("blockWith")), parameters_->Argument(context)));
+}
+
+CYExpression *CYTypeConstant::Replace_(CYContext &context, CYExpression *type) {
+    return next_->Replace(context, $ CYCall($ CYDirectMember(type, $ CYString("constant"))));
+}
+
+CYStatement *CYTypeDefinition::Replace(CYContext &context) {
+    return $E($ CYAssign($V(typed_->identifier_), typed_->Replace(context)));
+}
+
+CYExpression *CYTypeError::Replace(CYContext &context) {
+    _assert(false);
+    return NULL;
+}
+
+CYExpression *CYTypeModifier::Replace(CYContext &context, CYExpression *type) { $T(type)
+    return Replace_(context, type);
+}
+
+CYExpression *CYTypeFunctionWith::Replace_(CYContext &context, CYExpression *type) {
+    return next_->Replace(context, $ CYCall($ CYDirectMember(type, $ CYString("functionWith")), parameters_->Argument(context)));
+}
+
+CYExpression *CYTypeLong::Replace(CYContext &context) {
+    return $ CYCall($ CYDirectMember(specifier_->Replace(context), $ CYString("long")));
+}
+
+CYExpression *CYTypePointerTo::Replace_(CYContext &context, CYExpression *type) {
+    return next_->Replace(context, $ CYCall($ CYDirectMember(type, $ CYString("pointerTo"))));
+}
+
+CYExpression *CYTypeShort::Replace(CYContext &context) {
+    return $ CYCall($ CYDirectMember(specifier_->Replace(context), $ CYString("short")));
+}
+
+CYExpression *CYTypeSigned::Replace(CYContext &context) {
+    return $ CYCall($ CYDirectMember(specifier_->Replace(context), $ CYString("signed")));
+}
+
+CYExpression *CYTypeUnsigned::Replace(CYContext &context) {
+    return $ CYCall($ CYDirectMember(specifier_->Replace(context), $ CYString("unsigned")));
+}
+
+CYExpression *CYTypeVariable::Replace(CYContext &context) {
+    return $V(name_);
+}
+
+CYExpression *CYTypeVoid::Replace(CYContext &context) {
+    return $N1($V("Type"), $ CYString("v"));
+}
+
+CYExpression *CYTypeVolatile::Replace_(CYContext &context, CYExpression *type) {
+    return next_->Replace(context, $ CYCall($ CYDirectMember(type, $ CYString("volatile"))));
+}
+
+CYExpression *CYTypedIdentifier::Replace(CYContext &context) {
+    return modifier_->Replace(context, specifier_->Replace(context));
+}
+
+CYArgument *CYTypedParameter::Argument(CYContext &context) { $T(NULL)
+    return $ CYArgument(typed_->Replace(context), next_->Argument(context));
+}
+
+CYFunctionParameter *CYTypedParameter::Parameters(CYContext &context) { $T(NULL)
+    return $ CYFunctionParameter($ CYDeclaration(typed_->identifier_ ?: context.Unique()), next_->Parameters(context));
+}
+
+CYExpression *CYTypedParameter::TypeSignature(CYContext &context, CYExpression *prefix) { $T(prefix)
+    return next_->TypeSignature(context, $ CYAdd(prefix, typed_->Replace(context)));
+}
+
 CYStatement *CYVar::Replace(CYContext &context) {
     declarations_->Replace(context);
-    return $E(declarations_->Compound(context));
+    if (CYCompound *compound = declarations_->Compound(context))
+        return $E(compound);
+    return $ CYEmpty();
 }
 
 CYExpression *CYVariable::Replace(CYContext &context) {