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Simplify and normalize if block code

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This commit is contained in:
Jason Turner 2016-06-27 08:56:03 -06:00
parent e3d1741c63
commit 9e16cc2a79
4 changed files with 58 additions and 35 deletions
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4
include/chaiscript/language/chaiscript_engine.hpp
View File

@ -219,7 +219,7 @@ namespace chaiscript
std::vector<std::string> t_modulepaths = std::vector<std::string>(),
std::vector<std::string> t_usepaths = std::vector<std::string>())
: m_module_paths(std::move(t_modulepaths)), m_use_paths(std::move(t_usepaths)),
m_parser(std::make_unique<parser::ChaiScript_Parser<eval::Noop_Tracer, optimizer::Optimizer<optimizer::Block, optimizer::Partial_Fold, optimizer::Unused_Return, optimizer::Constant_Fold, optimizer::If, optimizer::Return, optimizer::For_Loop>>>()),
m_parser(std::make_unique<parser::ChaiScript_Parser<eval::Noop_Tracer, optimizer::Optimizer<optimizer::Partial_Fold, optimizer::Unused_Return, optimizer::Constant_Fold, optimizer::If, optimizer::Return, optimizer::Dead_Code, optimizer::Block, optimizer::For_Loop>>>()),
m_engine(*m_parser)
{
@ -246,7 +246,7 @@ namespace chaiscript
ChaiScript( std::vector<std::string> t_modulepaths = std::vector<std::string>(),
std::vector<std::string> t_usepaths = std::vector<std::string>())
: m_module_paths(std::move(t_modulepaths)), m_use_paths(std::move(t_usepaths)),
m_parser(std::make_unique<parser::ChaiScript_Parser<eval::Noop_Tracer, optimizer::Optimizer<optimizer::Block, optimizer::Partial_Fold, optimizer::Unused_Return, optimizer::Constant_Fold, optimizer::If, optimizer::Return, optimizer::For_Loop>>>()),
m_parser(std::make_unique<parser::ChaiScript_Parser<eval::Noop_Tracer, optimizer::Optimizer<optimizer::Partial_Fold, optimizer::Unused_Return, optimizer::Constant_Fold, optimizer::If, optimizer::Return, optimizer::Dead_Code, optimizer::Block, optimizer::For_Loop>>>()),
m_engine(*m_parser)
{
if (m_module_paths.empty())

43
include/chaiscript/language/chaiscript_eval.hpp
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@ -242,6 +242,12 @@ namespace chaiscript
{
}
Constant_AST_Node(Boxed_Value t_value)
: AST_Node_Impl<T>("", AST_Node_Type::Constant, Parse_Location()),
m_value(std::move(t_value))
{
}
Boxed_Value eval_internal(const chaiscript::detail::Dispatch_State &) const override {
return m_value;
}
@ -823,46 +829,20 @@ namespace chaiscript
};
template<typename T>
struct If_Init_AST_Node final : AST_Node_Impl<T> {
If_Init_AST_Node(std::string t_ast_node_text, Parse_Location t_loc, std::vector<AST_Node_Impl_Ptr<T>> t_children) :
AST_Node_Impl<T>(std::move(t_ast_node_text), AST_Node_Type::If, std::move(t_loc), std::move(t_children))
{
assert(this->children.size() == 3 || this->children.size() == 4);
}
Boxed_Value eval_internal(const chaiscript::detail::Dispatch_State &t_ss) const override {
chaiscript::eval::detail::Scope_Push_Pop spp(t_ss);
this->children[0]->eval(t_ss);
if (this->get_bool_condition(this->children[1]->eval(t_ss))) {
return this->children[2]->eval(t_ss);
} else {
if (this->children.size() == 4) {
return this->children[3]->eval(t_ss);
} else {
return void_var();
}
}
}
};
template<typename T>
struct If_AST_Node final : AST_Node_Impl<T> {
If_AST_Node(std::string t_ast_node_text, Parse_Location t_loc, std::vector<AST_Node_Impl_Ptr<T>> t_children) :
AST_Node_Impl<T>(std::move(t_ast_node_text), AST_Node_Type::If, std::move(t_loc), std::move(t_children))
{
assert(this->children.size() == 2 || this->children.size() == 3);
assert(this->children.size() == 3);
}
Boxed_Value eval_internal(const chaiscript::detail::Dispatch_State &t_ss) const override {
if (this->get_bool_condition(this->children[0]->eval(t_ss))) {
return this->children[1]->eval(t_ss);
} else {
if (this->children.size() == 3) {
return this->children[2]->eval(t_ss);
} else {
return void_var();
}
return this->children[2]->eval(t_ss);
}
}
};
@ -1227,10 +1207,11 @@ private:
{ }
Boxed_Value eval_internal(const chaiscript::detail::Dispatch_State &) const override{
// It's a no-op, that evaluates to "true"
// the magic-static version of const_var(true) helps us here
return const_var(true);
// It's a no-op, that evaluates to "void"
return val;
}
Boxed_Value val = void_var();
};
template<typename T>

34
include/chaiscript/language/chaiscript_optimizer.hpp
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@ -125,6 +125,40 @@ namespace chaiscript {
}
};
struct Dead_Code {
template<typename T>
auto optimize(const eval::AST_Node_Impl_Ptr<T> &node) {
if (node->identifier == AST_Node_Type::Block)
{
std::vector<size_t> keepers;
const auto num_children = node->children.size();
keepers.reserve(num_children);
for (size_t i = 0; i < num_children; ++i) {
auto child = node->children[i];
if ( (child->identifier != AST_Node_Type::Id
&& child->identifier != AST_Node_Type::Constant)
|| i == num_children - 1) {
keepers.push_back(i);
}
}
if (keepers.size() == num_children) {
return node;
} else {
std::vector<eval::AST_Node_Impl_Ptr<T>> new_children;
for (const auto x : keepers)
{
new_children.push_back(node->children[x]);
}
return chaiscript::make_shared<eval::AST_Node_Impl<T>, eval::Block_AST_Node<T>>(node->text, node->location, new_children);
}
} else {
return node;
}
}
};
struct Unused_Return {
template<typename T>
auto optimize(const eval::AST_Node_Impl_Ptr<T> &node) {

12
include/chaiscript/language/chaiscript_parser.hpp
View File

@ -1591,10 +1591,18 @@ namespace chaiscript
}
}
const auto num_children = m_match_stack.size() - prev_stack_top;
if ((is_if_init && num_children == 3)
|| (!is_if_init && num_children == 2)) {
m_match_stack.push_back(chaiscript::make_shared<eval::AST_Node_Impl<Tracer>, eval::Noop_AST_Node<Tracer>>());
}
if (!is_if_init) {
build_match<eval::If_AST_Node<Tracer>>(prev_stack_top);
} else {
build_match<eval::If_Init_AST_Node<Tracer>>(prev_stack_top);
build_match<eval::If_AST_Node<Tracer>>(prev_stack_top+1);
build_match<eval::Block_AST_Node<Tracer>>(prev_stack_top);
}
}
@ -1682,7 +1690,7 @@ namespace chaiscript
{
return false;
} else {
m_match_stack.push_back(chaiscript::make_shared<eval::AST_Node_Impl<Tracer>, eval::Noop_AST_Node<Tracer>>());
m_match_stack.push_back(chaiscript::make_shared<eval::AST_Node_Impl<Tracer>, eval::Constant_AST_Node<Tracer>>(Boxed_Value(true)));
}
}