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package scope
import (
"fmt"
"jinx/pkg/lang/vm/code"
)
type ScopeChain struct {
nameToSymbol map[string]SymbolID
symbolScopes []SymbolScope // All other scopes are bound to this by ID.
functionScopes []FunctionScope
}
func NewScopeChain() ScopeChain {
symbolScopes := make([]SymbolScope, 1)
symbolScopes[0] = NewSymbolScope()
functionScopes := make([]FunctionScope, 1)
functionScopes[0] = NewFunctionScope(0, "") // Root function to house top-scope sub units
return ScopeChain{
nameToSymbol: make(map[string]SymbolID),
symbolScopes: symbolScopes,
functionScopes: functionScopes,
}
}
func (sc *ScopeChain) CurrentScopeID() ScopeID {
return ScopeID(len(sc.symbolScopes) - 1)
}
func (sc *ScopeChain) IsRootScope() bool {
return sc.CurrentScopeID() == ScopeID(0)
}
func (sc *ScopeChain) Current() *SymbolScope {
if len(sc.functionScopes) == 0 {
panic("root scope is missing")
}
return &sc.symbolScopes[sc.CurrentScopeID()]
}
func (sc *ScopeChain) CurrentFunction() *FunctionScope {
if len(sc.functionScopes) == 0 {
panic("root function scope is missing")
}
return &sc.functionScopes[len(sc.functionScopes)-1]
}
func (sc *ScopeChain) Enter() {
sc.symbolScopes = append(sc.symbolScopes, NewSymbolScope())
}
func (sc *ScopeChain) EnterFunction(unit code.Marker) {
sc.Enter()
sc.functionScopes = append(sc.functionScopes, NewFunctionScope(sc.CurrentScopeID(), unit))
}
func (sc *ScopeChain) Exit() {
if sc.CurrentScopeID() == 0 {
return
}
sc.symbolScopes[sc.CurrentScopeID()] = SymbolScope{}
sc.symbolScopes = sc.symbolScopes[:sc.CurrentScopeID()]
}
func (sc *ScopeChain) Declare(name string) (int, bool) {
// Check whether the symbol is already declared in any of the scopes.
if _, ok := sc.nameToSymbol[name]; ok {
return 0, false
}
current := sc.Current()
indexInScope := len(current.variableSymbols)
symbolID := SymbolID{
symbolKind: SymbolKindVariable,
scopeID: sc.CurrentScopeID(),
indexInScope: indexInScope,
}
// Declare the symbol in the current scope.
current.variableSymbols = append(current.variableSymbols, Symbol[SymbolVariable]{
name: name,
data: SymbolVariable{
localIndex: indexInScope,
},
})
sc.nameToSymbol[name] = symbolID
return indexInScope, true
}
func (sc *ScopeChain) DeclareFunction(name string, args uint) (code.Marker, bool) {
if _, ok := sc.nameToSymbol[name]; ok {
return "", false
}
current := sc.Current()
index := len(current.functionSymbols)
symbolID := SymbolID{
symbolKind: SymbolKindFunction,
scopeID: sc.CurrentScopeID(),
indexInScope: index,
}
unitName := sc.CreateFunctionSubUnit(name)
current.functionSymbols = append(current.functionSymbols, Symbol[SymbolFunction]{
name: name,
data: SymbolFunction{
marker: unitName,
args: args,
},
})
sc.nameToSymbol[name] = symbolID
return unitName, true
}
func (sc *ScopeChain) DeclareAnonymous() int {
current := sc.Current()
index := len(current.variableSymbols)
current.variableSymbols = append(current.variableSymbols, Symbol[SymbolVariable]{
name: "", // An anonymous symbol has no name.
data: SymbolVariable{
localIndex: index,
},
})
return index
}
func (sc *ScopeChain) DeclareTemporary() int {
return len(sc.Current().variableSymbols) // :)
}
func (sc *ScopeChain) CreateAnonymousFunctionSubUnit() code.Marker {
fnScope := sc.CurrentFunction()
index := fnScope.subUnitCount
fnScope.subUnitCount++
return sc.CreateFunctionSubUnit(fmt.Sprintf("anon_%d", index))
}
func (sc *ScopeChain) CreateFunctionSubUnit(subUnitName string) code.Marker {
fnScope := sc.CurrentFunction()
name := fnScope.unit
if name == "" {
name = code.Marker(subUnitName)
} else {
name = name.SubUnit(subUnitName)
}
return name
}
func (sc *ScopeChain) Lookup(name string) (SymbolID, bool) {
if id, ok := sc.nameToSymbol[name]; ok {
return id, true
}
return SymbolID{}, false
}
func (sc *ScopeChain) GetVariable(id SymbolID) Symbol[SymbolVariable] {
if id.symbolKind != SymbolKindVariable {
panic("incorrect symbol id kind given")
}
return sc.symbolScopes[id.scopeID].variableSymbols[id.indexInScope]
}
func (sc *ScopeChain) GetFunction(id SymbolID) Symbol[SymbolFunction] {
if id.symbolKind != SymbolKindFunction {
panic("incorrect symbol id kind given")
}
return sc.symbolScopes[id.scopeID].functionSymbols[id.indexInScope]
}
|
