114 lines
3.9 KiB
C++
114 lines
3.9 KiB
C++
/** @file DLocalSymtab.hpp
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*
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* @author Roland Conybeare, Jan 2026
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**/
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#pragma once
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#include "Binding.hpp"
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#include "DVariable.hpp"
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#include "DUniqueString.hpp"
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//#include "exprtype.hpp"
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//#include <xo/reflect/TaggedPtr.hpp>
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//#include <xo/gc/GCObject.hpp>
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namespace xo {
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namespace scm {
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/** @class DLocalSymtab
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* @brief symbol table for a local stack frame
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**/
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struct DLocalSymtab {
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public:
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// using TaggedPtr = xo::reflect::TaggedPtr;
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// using TypeDescr = xo::reflect::TypeDescr;
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// using AGCObject = xo::mm::AGCObject;
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// using typeseq = xo::reflect::typeseq;
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using ppindentinfo = xo::print::ppindentinfo;
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using AAllocator = xo::mm::AAllocator;
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/* note: uint16_t would be fine too */
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using size_type = std::uint32_t;
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struct Slot {
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Slot() = default;
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explicit Slot(const DVariable * var) : var_{var} {}
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/** variable representing a formal argument.
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* binding will be correct only within the same layer
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* as top-level lambda body
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* (i.e. up to the doorstep of each and every nested lambda)
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**/
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const DVariable * var_ = nullptr;
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};
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public:
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/** @defgroup scm-lambdaexpr-constructors **/
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///@{
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/** empty instance with parent @p p and capacity for @p n slots.
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* Caller must ensure that slots_[0..n) are actually addressable
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**/
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DLocalSymtab(DLocalSymtab * p, size_type n);
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/** scaffold empty symtab instance,
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* with capacity for @p n slots, using memory from allocator @p mm
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**/
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static DLocalSymtab * _make_empty(obj<AAllocator> mm,
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DLocalSymtab * p,
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size_type n);
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///@}
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/** @defgroup scm-lambdaexpr-methods **/
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///@{
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DLocalSymtab * parent() const noexcept { return parent_; }
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size_type capacity() const noexcept { return capacity_; }
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size_type size() const noexcept { return size_; }
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const DVariable * lookup_var(Binding ix) const noexcept {
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assert(ix.i_link() == 0);
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assert(ix.j_slot() < static_cast<int32_t>(size_));
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return slots_[ix.j_slot()].var_;
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}
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/** increase slot size (provided beleow capacity) to append
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* binding for one local variable. Local variable will be allocated
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* from @p mm, named @p name, with type described by @p typeref.
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**/
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Binding append_var(obj<AAllocator> mm,
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const DUniqueString * name,
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TypeRef typeref);
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///@}
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/** @defgroup xo-localsymtab-symboltable-facet symboltable facet**/
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///@{
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/** true for global symbol table **/
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bool is_global_symtab() const noexcept { return false; }
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/** lookup binding for variable @p sym **/
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Binding lookup_binding(const DUniqueString * sym) const noexcept;
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///@}
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/** @defgroup xo-localsymtab-printable-facet printable facet **/
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///@{
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bool pretty(const ppindentinfo & ppii) const;
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///@}
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private:
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/** parent symbol table from scoping surrounding this one **/
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DLocalSymtab * parent_ = nullptr;
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/** actual range of slots_[] array. Can use inices in [0,..,n) **/
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size_type capacity_ = 0;
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/** number of slots in use **/
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size_type size_ = 0;
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/** memory for names and bindings **/
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Slot slots_[];
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};
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} /*namespace scm*/
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} /*namespace xo*/
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/* end DLocalSymtab.hpp */
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