X-Git-Url: https://git.saurik.com/cycript.git/blobdiff_plain/1071182333f1fc0c0de118d374727a66ebd3805a..66170b30c7577168b02b9980304f35026a94de1a:/Replace.cpp?ds=sidebyside

diff --git a/Replace.cpp b/Replace.cpp
index 37b7068..acf4d51 100644
--- a/Replace.cpp
+++ b/Replace.cpp
@@ -1,40 +1,22 @@
-/* Cycript - Inlining/Optimizing JavaScript Compiler
- * Copyright (C) 2009  Jay Freeman (saurik)
+/* Cycript - Optimizing JavaScript Compiler/Runtime
+ * Copyright (C) 2009-2012  Jay Freeman (saurik)
 */
 
-/* Modified BSD License {{{ */
+/* GNU Lesser General Public License, Version 3 {{{ */
 /*
- *        Redistribution and use in source and binary
- * forms, with or without modification, are permitted
- * provided that the following conditions are met:
+ * 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.
  *
- * 1. Redistributions of source code must retain the
- *    above copyright notice, this list of conditions
- *    and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the
- *    above copyright notice, this list of conditions
- *    and the following disclaimer in the documentation
- *    and/or other materials provided with the
- *    distribution.
- * 3. The name of the author may not be used to endorse
- *    or promote products derived from this software
- *    without specific prior written permission.
+ * 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.
  *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS''
- * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
- * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
- * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE
- * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
- * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
- * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
- * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
- * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
- * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
- * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
- * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
- * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-*/
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with Cycript.  If not, see <http://www.gnu.org/licenses/>.
+**/
 /* }}} */
 
 #include "Parser.hpp"
@@ -42,6 +24,11 @@
 
 #include <iomanip>
 
+CYFunctionExpression *CYNonLocalize(CYContext &context, CYFunctionExpression *function) {
+    function->nonlocal_ = context.nextlocal_;
+    return function;
+}
+
 CYExpression *CYAdd::Replace(CYContext &context) {
     CYInfix::Replace(context);
 
@@ -73,13 +60,21 @@ CYExpression *CYAdd::Replace(CYContext &context) {
 }
 
 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) {
@@ -90,7 +85,7 @@ 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)
@@ -104,7 +99,7 @@ CYExpression *CYAssignment::Replace(CYContext &context) {
 }
 
 CYStatement *CYBlock::Replace(CYContext &context) {
-    statements_ = statements_->ReplaceAll(context);
+    context.ReplaceAll(statements_);
     if (statements_ == NULL)
         return $ CYEmpty();
     return this;
@@ -114,6 +109,14 @@ CYStatement *CYBreak::Replace(CYContext &context) {
     return this;
 }
 
+CYExpression *CYCall::AddArgument(CYContext &context, CYExpression *value) {
+    CYArgument **argument(&arguments_);
+    while (*argument != NULL)
+        argument = &(*argument)->next_;
+    *argument = $ CYArgument(value);
+    return this;
+}
+
 CYExpression *CYCall::Replace(CYContext &context) {
     context.Replace(function_);
     arguments_->Replace(context);
@@ -124,14 +127,20 @@ namespace cy {
 namespace Syntax {
 
 void Catch::Replace(CYContext &context) { $T()
+    CYScope scope(true, context, code_.statements_);
+
+    context.Replace(name_);
+    context.scope_->Declare(context, name_, CYIdentifierCatch);
+
     code_.Replace(context);
+    scope.Close();
 }
 
 } }
 
 void CYClause::Replace(CYContext &context) { $T()
     context.Replace(case_);
-    statements_ = statements_->ReplaceAll(context);
+    context.ReplaceAll(statements_);
     next_->Replace(context);
 }
 
@@ -140,8 +149,19 @@ CYStatement *CYComment::Replace(CYContext &context) {
 }
 
 CYExpression *CYCompound::Replace(CYContext &context) {
-    expressions_ = expressions_->ReplaceAll(context);
-    return expressions_ == NULL ? NULL : this;
+    context.ReplaceAll(expressions_);
+    if (expressions_ == NULL)
+        return NULL;
+    return this;
+}
+
+CYExpression *CYCompound::Primitive(CYContext &context) {
+    CYExpression *expression(expressions_);
+    if (expression == NULL)
+        return NULL;
+    while (expression->next_ != NULL)
+        expression = expression->next_;
+    return expression->Primitive(context);
 }
 
 CYFunctionParameter *CYComprehension::Parameters(CYContext &context) const { $T(NULL)
@@ -164,46 +184,93 @@ CYExpression *CYCondition::Replace(CYContext &context) {
     return this;
 }
 
+void CYContext::NonLocal(CYStatement *&statements) {
+    CYContext &context(*this);
+
+    if (nextlocal_ != NULL && nextlocal_->identifier_ != NULL) {
+        CYIdentifier *cye($I("$cye")->Replace(context));
+        CYIdentifier *unique(nextlocal_->identifier_->Replace(context));
+
+        CYStatement *declare(
+            $ CYVar($L1($ CYDeclaration(unique, $ CYObject()))));
+
+        cy::Syntax::Catch *rescue(
+            $ cy::Syntax::Catch(cye, $$->*
+                $ CYIf($ CYIdentical($M($V(cye), $S("$cyk")), $V(unique)), $$->*
+                    $ CYReturn($M($V(cye), $S("$cyv"))))->*
+                $ cy::Syntax::Throw($V(cye))));
+
+        context.Replace(declare);
+        rescue->Replace(context);
+
+        statements = $$->*
+            declare->*
+            $ cy::Syntax::Try(statements, rescue, NULL);
+    }
+}
+
+CYIdentifier *CYContext::Unique() {
+    return $ CYIdentifier(apr_psprintf($pool, "$cy%u", unique_++));
+}
+
 CYStatement *CYContinue::Replace(CYContext &context) {
     return this;
 }
 
+CYStatement *CYDebugger::Replace(CYContext &context) {
+    return this;
+}
+
 CYAssignment *CYDeclaration::Assignment(CYContext &context) {
-    CYExpression *variable(Replace(context));
-    return initialiser_ == NULL ? NULL : $ CYAssign(variable, initialiser_);
+    if (initialiser_ == NULL)
+        return NULL;
+
+    CYAssignment *value($ CYAssign(Variable(context), initialiser_));
+    initialiser_ = NULL;
+    return value;
+}
+
+CYVariable *CYDeclaration::Variable(CYContext &context) {
+    return $V(identifier_);
 }
 
-CYExpression *CYDeclaration::ForEachIn(CYContext &context) {
-    return $ CYVariable(identifier_);
+CYStatement *CYDeclaration::ForEachIn(CYContext &context, CYExpression *value) {
+    return $ CYVar($L1($ CYDeclaration(identifier_, value)));
 }
 
 CYExpression *CYDeclaration::Replace(CYContext &context) {
     context.Replace(identifier_);
     context.scope_->Declare(context, identifier_, CYIdentifierVariable);
-    return $ CYVariable(identifier_);
+    return Variable(context);
+}
+
+void CYDeclarations::Replace(CYContext &context) { $T()
+    declaration_->Replace(context);
+    next_->Replace(context);
 }
 
 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));
 }
 
-CYCompound *CYDeclarations::Replace(CYContext &context) {
-    CYCompound *compound;
-    if (next_ == NULL) compound:
-        compound = $ CYCompound();
-    else {
-        compound = next_->Replace(context);
-        if (compound == NULL)
-            goto compound;
-    }
+CYFunctionParameter *CYDeclarations::Parameter(CYContext &context) { $T(NULL)
+    return $ CYFunctionParameter($ CYDeclaration(declaration_->identifier_), next_->Parameter(context));
+}
+
+CYArgument *CYDeclarations::Argument(CYContext &context) { $T(NULL)
+    return $ CYArgument(declaration_->initialiser_, next_->Argument(context));
+}
 
+CYCompound *CYDeclarations::Compound(CYContext &context) { $T(NULL)
+    CYCompound *compound(next_->Compound(context) ?: $ CYCompound());
     if (CYAssignment *assignment = declaration_->Assignment(context))
         compound->AddPrev(assignment);
     return compound;
 }
 
 CYExpression *CYDirectMember::Replace(CYContext &context) {
-    Replace_(context);
+    context.Replace(object_);
+    context.Replace(property_);
     return this;
 }
 
@@ -218,52 +285,41 @@ void CYElement::Replace(CYContext &context) { $T()
     next_->Replace(context);
 }
 
-CYStatement *CYEmpty::Collapse(CYContext &context) {
-    return next_;
-}
-
 CYStatement *CYEmpty::Replace(CYContext &context) {
-    return this;
+    return NULL;
 }
 
-CYStatement *CYExpress::Collapse(CYContext &context) {
-    if (CYExpress *express = dynamic_cast<CYExpress *>(next_)) {
-        CYCompound *next(dynamic_cast<CYCompound *>(express->expression_));
-        if (next == NULL)
-            next = $ CYCompound(express->expression_);
-        next->AddPrev(expression_);
-        expression_ = next;
+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;
         SetNext(express->next_);
     }
 
-    return this;
-}
-
-CYStatement *CYExpress::Replace(CYContext &context) {
     context.Replace(expression_);
     if (expression_ == NULL)
         return $ CYEmpty();
+
     return this;
 }
 
-CYExpression *CYExpression::ClassName(CYContext &context, bool object) {
-    return this;
+CYExpression *CYExpression::AddArgument(CYContext &context, CYExpression *value) {
+    return $C1(this, value);
 }
 
-CYExpression *CYExpression::ForEachIn(CYContext &context) {
+CYExpression *CYExpression::ClassName(CYContext &context, bool object) {
     return this;
 }
 
-CYExpression *CYExpression::ReplaceAll(CYContext &context) { $T(NULL)
-    CYExpression *replace(this);
-    context.Replace(replace);
-
-    if (CYExpression *next = next_->ReplaceAll(context))
-        replace->SetNext(next);
-    else
-        replace->SetNext(next_);
+CYStatement *CYExpression::ForEachIn(CYContext &context, CYExpression *value) {
+    return $E($ CYAssign(this, value));
+}
 
-    return replace;
+CYAssignment *CYExpression::Assignment(CYContext &context) {
+    return NULL;
 }
 
 CYNumber *CYFalse::Number(CYContext &context) {
@@ -274,6 +330,12 @@ 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);
 }
@@ -286,8 +348,19 @@ CYStatement *CYFor::Replace(CYContext &context) {
     return this;
 }
 
+CYCompound *CYForDeclarations::Replace(CYContext &context) {
+    declarations_->Replace(context);
+    return declarations_->Compound(context);
+}
+
+// XXX: this still feels highly suboptimal
 CYStatement *CYForIn::Replace(CYContext &context) {
-    // XXX: this actually might need a prefix statement
+    if (CYAssignment *assignment = initialiser_->Assignment(context))
+        return $ CYBlock($$->*
+            $E(assignment)->*
+            this
+        );
+
     context.Replace(initialiser_);
     context.Replace(set_);
     context.Replace(code_);
@@ -295,35 +368,41 @@ 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($ CYVariable(name_), set_, CYComprehension::Replace(context, statement));
+    return $ CYForIn($V(name_), set_, CYComprehension::Replace(context, statement));
 }
 
-CYStatement *CYForEachIn::Replace(CYContext &context) {
-    CYVariable *cys($V("$cys")), *cyt($V("$cyt"));
+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($I("$cys"), set_), $L($I("$cyt"))), $$->*
-        $ CYForIn(cyt, cys, $ CYBlock($$->*
-            $E($ CYAssign(initialiser_->ForEachIn(context), $M(cys, cyt)))->*
+    return $ CYLetStatement($L2($ CYDeclaration(cys, set_), $ CYDeclaration(cyt)), $$->*
+        $ CYForIn($V(cyt), $V(cys), $ CYBlock($$->*
+            initialiser_->ForEachIn(context, $M($V(cys), $V(cyt)))->*
             code_
         ))
     );
 }
 
-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 {
-    CYVariable *cys($V("$cys")), *name($ CYVariable(name_));
+CYStatement *CYForOfComprehension::Replace(CYContext &context, CYStatement *statement) const {
+    CYIdentifier *cys($I("cys"));
 
-    return $E($C0($F(NULL, $P1("$cys"), $$->*
-        $E($ CYAssign(cys, set_))->*
-        $ CYForIn(name, cys, $ CYBlock($$->*
-            $E($ CYAssign(name, $M(cys, name)))->*
+    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_))))->*
             CYComprehension::Replace(context, statement)
         ))
     )));
@@ -338,17 +417,44 @@ void CYFunction::Replace_(CYContext &context, bool outer) {
     if (outer)
         Inject(context);
 
-    parent_ = context.scope_;
-    context.scope_ = this;
+    CYThisScope *_this(context.this_);
+    context.this_ = CYGetLast(&this_);
+
+    CYNonLocal *nonlocal(context.nonlocal_);
+    CYNonLocal *nextlocal(context.nextlocal_);
+
+    bool localize;
+    if (nonlocal_ != NULL) {
+        localize = false;
+        context.nonlocal_ = nonlocal_;
+    } else {
+        localize = true;
+        nonlocal_ = $ CYNonLocal();
+        context.nextlocal_ = nonlocal_;
+    }
+
+    CYScope scope(!localize, context, code_.statements_);
 
     if (!outer && name_ != NULL)
         Inject(context);
 
-    parameters_->Replace(context);
+    parameters_->Replace(context, code_);
     code_.Replace(context);
 
-    context.scope_ = parent_;
-    Scope(context, code_.statements_);
+    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();
 }
 
 CYExpression *CYFunctionExpression::Replace(CYContext &context) {
@@ -356,10 +462,17 @@ CYExpression *CYFunctionExpression::Replace(CYContext &context) {
     return this;
 }
 
-void CYFunctionParameter::Replace(CYContext &context) { $T()
-    name_ = name_->Replace(context);
-    context.scope_->Declare(context, name_, CYIdentifierArgument);
-    next_->Replace(context);
+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) {
@@ -368,8 +481,9 @@ CYStatement *CYFunctionStatement::Replace(CYContext &context) {
 }
 
 CYIdentifier *CYIdentifier::Replace(CYContext &context) {
-    if (replace_ == NULL)
-        replace_ = context.scope_->Lookup(context, this);
+    if (replace_ != NULL && replace_ != this)
+        return replace_->Replace(context);
+    replace_ = context.scope_->Lookup(context, this);
     return replace_;
 }
 
@@ -389,12 +503,10 @@ 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_);
 }
 
@@ -409,21 +521,26 @@ CYStatement *CYLabel::Replace(CYContext &context) {
     return this;
 }
 
-CYStatement *CYLet::Replace(CYContext &context) {
-    return $ CYWith($ CYObject(declarations_->Property(context)), &code_);
+CYStatement *CYLetStatement::Replace(CYContext &context) {
+    return $E($ CYCall(CYNonLocalize(context, $ CYFunctionExpression(NULL, declarations_->Parameter(context), code_)), declarations_->Argument(context)));
 }
 
-void CYMember::Replace_(CYContext &context) {
-    context.Replace(object_);
-    context.Replace(property_);
+namespace cy {
+namespace Syntax {
+
+CYExpression *New::AddArgument(CYContext &context, CYExpression *value) {
+    CYSetLast(arguments_) = $ CYArgument(value);
+    return this;
 }
 
-CYExpression *CYNew::Replace(CYContext &context) {
+CYExpression *New::Replace(CYContext &context) {
     context.Replace(constructor_);
     arguments_->Replace(context);
     return this;
 }
 
+} }
+
 CYNumber *CYNull::Number(CYContext &context) {
     return $D(0);
 }
@@ -438,7 +555,7 @@ CYNumber *CYNumber::Number(CYContext &context) {
 
 CYString *CYNumber::String(CYContext &context) {
     // XXX: there is a precise algorithm for this
-    return $S(apr_psprintf(context.pool_, "%.17g", Value()));
+    return $S(apr_psprintf($pool, "%.17g", Value()));
 }
 
 CYExpression *CYObject::Replace(CYContext &context) {
@@ -460,31 +577,49 @@ CYExpression *CYPrefix::Replace(CYContext &context) {
 #define MappingSet "0etnirsoalfucdphmgyvbxTwSNECAFjDLkMOIBPqzRH$_WXUVGYKQJZ"
 //#define MappingSet "0abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ$_"
 
-void CYProgram::Replace(CYContext &context) {
-    parent_ = context.scope_;
-    CYProgram *program(context.program_);
+namespace {
+    struct IdentifierUsageLess :
+        std::binary_function<CYIdentifier *, CYIdentifier *, bool>
+    {
+        _finline bool operator ()(CYIdentifier *lhs, CYIdentifier *rhs) const {
+            if (lhs->usage_ != rhs->usage_)
+                return lhs->usage_ > rhs->usage_;
+            return lhs < rhs;
+        }
+    };
+
+    typedef std::set<CYIdentifier *, IdentifierUsageLess> IdentifierUsages;
+}
 
-    context.scope_ = this;
-    context.program_ = this;
+void CYProgram::Replace(CYContext &context) {
+    CYScope scope(true, context, statements_);
 
-    statements_ = statements_->ReplaceAll(context);
+    context.nextlocal_ = $ CYNonLocal();
+    context.ReplaceAll(statements_);
+    context.NonLocal(statements_);
 
-    context.scope_ = parent_;
-    context.program_ = program;
-    Scope(context, statements_);
+    scope.Close();
 
     size_t offset(0);
 
     CYCStringSet external;
-    for (CYIdentifierValueSet::const_iterator i(identifiers_.begin()); i != identifiers_.end(); ++i)
+    for (CYIdentifierValueSet::const_iterator i(scope.identifiers_.begin()); i != scope.identifiers_.end(); ++i)
         external.insert((*i)->Word());
 
+    IdentifierUsages usages;
+
+    if (offset < context.rename_.size())
+        CYForEach (i, context.rename_[offset].identifier_)
+            usages.insert(i);
+
     // XXX: totalling the probable occurrences and sorting by them would improve the result
-    for (CYIdentifierAddressVector::const_iterator i(rename_.begin()); i != rename_.end(); ++i, ++offset) {
+    for (CYIdentifierUsageVector::const_iterator i(context.rename_.begin()); i != context.rename_.end(); ++i, ++offset) {
+        //std::cout << *i << ":" << (*i)->offset_ << std::endl;
+
         const char *name;
 
         if (context.options_.verbose_)
-            name = apr_psprintf(context.pool_, "$%"APR_SIZE_T_FMT"", offset);
+            name = apr_psprintf($pool, "$%"APR_SIZE_T_FMT"", offset);
         else {
             char id[8];
             id[7] = '\0';
@@ -503,11 +638,11 @@ void CYProgram::Replace(CYContext &context) {
                 goto id;
             }
 
-            name = apr_pstrmemdup(context.pool_, id + position, 7 - position);
+            name = apr_pstrmemdup($pool, id + position, 7 - position);
             // XXX: at some point, this could become a keyword
         }
 
-        for (CYIdentifier *identifier(*i); identifier != NULL; identifier = identifier->next_)
+        CYForEach (identifier, i->identifier_)
             identifier->Set(name);
     }
 }
@@ -515,15 +650,53 @@ 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) {
+    if (context.nonlocal_ != NULL) {
+        CYProperty *value(value_ == NULL ? NULL : $ CYProperty($S("$cyv"), value_));
+        return $ cy::Syntax::Throw($ CYObject(
+            $ CYProperty($S("$cyk"), $V(context.nonlocal_->Target(context)), value)
+        ));
+    }
+
     context.Replace(value_);
     return this;
 }
 
+CYExpression *CYRubyBlock::Replace(CYContext &context) {
+    // XXX: this needs to do something much more epic to handle return
+    return call_->AddArgument(context, proc_->Replace(context));
+}
+
+CYExpression *CYRubyProc::Replace(CYContext &context) {
+    return CYNonLocalize(context, $ CYFunctionExpression(NULL, parameters_, code_));
+}
+
+CYScope::CYScope(bool transparent, CYContext &context, CYStatement *&statements) :
+    transparent_(transparent),
+    context_(context),
+    statements_(statements),
+    parent_(context.scope_)
+{
+    context_.scope_ = this;
+}
+
+CYScope::~CYScope() {
+}
+
+void CYScope::Close() {
+    context_.scope_ = parent_;
+    Scope(context_, statements_);
+}
+
 void CYScope::Declare(CYContext &context, CYIdentifier *identifier, CYIdentifierFlags flags) {
-    internal_.insert(CYIdentifierAddressFlagsMap::value_type(identifier, flags));
+    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) {
@@ -537,6 +710,7 @@ void CYScope::Merge(CYContext &context, CYIdentifier *identifier) {
         if ((*insert.first)->offset_ < identifier->offset_)
             (*insert.first)->offset_ = identifier->offset_;
         identifier->replace_ = *insert.first;
+        (*insert.first)->usage_ += identifier->usage_ + 1;
     }
 }
 
@@ -544,11 +718,13 @@ namespace {
     struct IdentifierOffset {
         size_t offset_;
         CYIdentifierFlags flags_;
+        size_t usage_;
         CYIdentifier *identifier_;
 
-        IdentifierOffset(size_t offset, CYIdentifierFlags flags, CYIdentifier *identifier) :
-            offset_(offset),
+        IdentifierOffset(CYIdentifier *identifier, CYIdentifierFlags flags) :
+            offset_(identifier->offset_),
             flags_(flags),
+            usage_(identifier->usage_),
             identifier_(identifier)
         {
         }
@@ -562,6 +738,8 @@ namespace {
                 return lhs.offset_ < rhs.offset_;
             if (lhs.flags_ != rhs.flags_)
                 return lhs.flags_ < rhs.flags_;
+            /*if (lhs.usage_ != rhs.usage_)
+                return lhs.usage_ < rhs.usage_;*/
             return lhs.identifier_ < rhs.identifier_;
         }
     };
@@ -570,15 +748,16 @@ namespace {
 }
 
 void CYScope::Scope(CYContext &context, CYStatement *&statements) {
+    if (parent_ == NULL)
+        return;
+
     CYDeclarations *last(NULL), *curr(NULL);
-    CYProgram *program(context.program_);
 
     IdentifierOffsets offsets;
 
-    // XXX: we don't want to do this in order, we want to sort it by probable occurrence
     for (CYIdentifierAddressFlagsMap::const_iterator i(internal_.begin()); i != internal_.end(); ++i)
-        if (program != NULL && i->second != CYIdentifierMagic)
-            offsets.insert(IdentifierOffset(i->first->offset_, i->second, i->first));
+        if (i->second != CYIdentifierMagic)
+            offsets.insert(IdentifierOffset(i->first, i->second));
 
     size_t offset(0);
 
@@ -594,12 +773,13 @@ void CYScope::Scope(CYContext &context, CYStatement *&statements) {
 
         if (offset < i->offset_)
             offset = i->offset_;
-        if (program->rename_.size() <= offset)
-            program->rename_.resize(offset + 1);
+        if (context.rename_.size() <= offset)
+            context.rename_.resize(offset + 1);
 
-        CYIdentifier *&identifier(program->rename_[offset++]);
-        i->identifier_->SetNext(identifier);
-        identifier = i->identifier_;
+        CYIdentifierUsage &rename(context.rename_[offset++]);
+        i->identifier_->SetNext(rename.identifier_);
+        rename.identifier_ = i->identifier_;
+        rename.usage_ += i->identifier_->usage_ + 1;
     }
 
     if (last != NULL) {
@@ -610,26 +790,16 @@ void CYScope::Scope(CYContext &context, CYStatement *&statements) {
 
     for (CYIdentifierValueSet::const_iterator i(identifiers_.begin()); i != identifiers_.end(); ++i)
         if (internal_.find(*i) == internal_.end()) {
+            //std::cout << *i << '=' << offset << std::endl;
             if ((*i)->offset_ < offset)
                 (*i)->offset_ = offset;
             parent_->Merge(context, *i);
         }
 }
 
-CYStatement *CYStatement::Collapse(CYContext &context) {
-    return this;
-}
-
-CYStatement *CYStatement::ReplaceAll(CYContext &context) { $T(NULL)
-    CYStatement *replace(this);
-    context.Replace(replace);
-    replace->SetNext(next_->ReplaceAll(context));
-    return replace->Collapse(context);
-}
-
 CYString *CYString::Concat(CYContext &context, CYString *rhs) const {
     size_t size(size_ + rhs->size_);
-    char *value(new(context.pool_) char[size + 1]);
+    char *value($ char[size + 1]);
     memcpy(value, value_, size_);
     memcpy(value + size_, rhs->value_, rhs->size_);
     value[size] = '\0';
@@ -652,6 +822,8 @@ CYStatement *CYSwitch::Replace(CYContext &context) {
 }
 
 CYExpression *CYThis::Replace(CYContext &context) {
+    if (context.this_ != NULL)
+        return $V(context.this_->Identifier(context));
     return this;
 }
 
@@ -690,11 +862,12 @@ CYStatement *Try::Replace(CYContext &context) {
 } }
 
 CYStatement *CYVar::Replace(CYContext &context) {
-    return $E(declarations_->Replace(context));
+    declarations_->Replace(context);
+    return $E(declarations_->Compound(context));
 }
 
 CYExpression *CYVariable::Replace(CYContext &context) {
-    name_ = name_->Replace(context);
+    context.Replace(name_);
     return this;
 }