98 lines
2.5 KiB
C++
98 lines
2.5 KiB
C++
/* file envframestack.cpp
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*
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* author: Roland Conybeare
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*/
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#include "envframestack.hpp"
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namespace xo {
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using xo::ast::LocalEnv;
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using xo::ast::Variable;
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namespace scm {
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bp<LocalEnv>
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envframestack::top_envframe() {
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std::size_t z = stack_.size();
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if (z == 0) {
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throw std::runtime_error
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("parser::top_exprstate: unexpected empty stack");
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}
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return stack_[z-1].get();
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}
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void
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envframestack::push_envframe(const rp<LocalEnv> & frame)
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{
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constexpr bool c_debug_flag = true;
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scope log(XO_DEBUG(c_debug_flag),
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xtag("frame", frame));
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std::size_t z = stack_.size();
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stack_.resize(z+1);
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stack_[z] = frame;
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}
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rp<LocalEnv>
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envframestack::pop_envframe() {
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constexpr bool c_debug_flag = true;
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scope log(XO_DEBUG(c_debug_flag));
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std::size_t z = stack_.size();
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if (z > 0) {
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//std::unique_ptr<exprstate> top = std::move(stack_[z-1]);
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rp<LocalEnv> retval = stack_.at(z-1);
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stack_.resize(z-1);
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return retval;
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} else {
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return nullptr;
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}
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}
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bp<Variable>
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envframestack::lookup(const std::string & x) const {
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for (std::size_t i = 0, z = this->size(); i < z; ++i) {
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const auto & frame = (*this)[i];
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auto retval = frame->lookup_local(x);
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if (retval)
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return retval;
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}
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return bp<Variable>::from_native(nullptr);
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}
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void
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envframestack::upsert(bp<Variable> x) {
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/* upsert should always happen in the innermost lexical context.
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* We are providing new variable binding (perhaps shadowing an existing binding)
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*/
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this->top_envframe()->upsert_local(x);
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}
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void
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envframestack::print(std::ostream & os) const {
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os << "<envframestack"
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<< xtag("size", stack_.size())
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<< std::endl;
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for (std::size_t i = 0, z = stack_.size(); i < z; ++i) {
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os << " [" << z-i-1 << "] "
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<< stack_[i]
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<< std::endl;
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}
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os << ">" << std::endl;
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}
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} /*namespace scm*/
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} /*namespace xo*/
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/* end envframestack.cpp */
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