63 lines
1.1 KiB
Go
63 lines
1.1 KiB
Go
package compiler
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type SymbolScope string
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const (
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LocalScope SymbolScope = "LOCAL"
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GlobalScope SymbolScope = "GLOBAL"
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BuiltinScope SymbolScope = "BUILTIN"
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)
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type Symbol struct {
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Name string
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Scope SymbolScope
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Index int
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}
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type SymbolTable struct {
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Outer *SymbolTable
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store map[string]Symbol
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numDefinitions int
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}
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func NewEnclosedSymbolTable(outer *SymbolTable) *SymbolTable {
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s := NewSymbolTable()
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s.Outer = outer
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return s
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}
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func NewSymbolTable() *SymbolTable {
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s := make(map[string]Symbol)
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return &SymbolTable{store: s}
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}
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func (s *SymbolTable) Define(name string) Symbol {
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symbol := Symbol{Name: name, Index: s.numDefinitions}
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if s.Outer == nil {
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symbol.Scope = GlobalScope
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} else {
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symbol.Scope = LocalScope
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}
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s.store[name] = symbol
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s.numDefinitions++
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return symbol
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}
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func (s *SymbolTable) Resolve(name string) (Symbol, bool) {
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obj, ok := s.store[name]
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if !ok && s.Outer != nil {
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obj, ok = s.Outer.Resolve(name)
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return obj, ok
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}
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return obj, ok
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}
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func (s *SymbolTable) DefineBuiltin(index int, name string) Symbol {
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symbol := Symbol{Name: name, Index: index, Scope: BuiltinScope}
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s.store[name] = symbol
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return symbol
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}
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