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|
package compiler
import (
"fmt"
"jinx/pkg/lang/vm/code"
)
type ScopeID int
type ScopeChain struct {
nameToSymbol map[string]SymbolID
scopes []Scope
}
func NewScopeChain() ScopeChain {
scopes := make([]Scope, 1)
scopes[0] = NewFunctionScope(0, "") // Top-most scope is a function scope, so it can have sub-units
return ScopeChain{
nameToSymbol: make(map[string]SymbolID),
scopes: scopes,
}
}
func (sc *ScopeChain) CurrentScopeID() ScopeID {
return ScopeID(len(sc.scopes) - 1)
}
func (sc *ScopeChain) IsRootScope() bool {
return sc.CurrentScopeID() == ScopeID(0)
}
func (sc *ScopeChain) Current() *Scope {
return &sc.scopes[sc.CurrentScopeID()]
}
func (sc *ScopeChain) CurrentFunction() *Scope {
// TODO: Probably should make this lookup constant by making a seperate array of function scopes
for i := len(sc.scopes) - 1; i >= 0; i++ {
if sc.scopes[i].kind == ScopeKindFunction {
return &sc.scopes[i]
}
}
panic("top scope should always be a function scope")
}
func (sc *ScopeChain) Enter() {
sc.scopes = append(sc.scopes, NewNormalScope())
}
func (sc *ScopeChain) EnterFunction(unit code.Marker) {
id := sc.CurrentScopeID() + 1
sc.scopes = append(sc.scopes, NewFunctionScope(id, unit))
}
func (sc *ScopeChain) Exit() {
if sc.CurrentScopeID() == 0 {
return
}
sc.scopes[sc.CurrentScopeID()] = Scope{}
sc.scopes = sc.scopes[: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) (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,
},
})
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()
data := fnScope.data.(ScopeFunction)
index := data.subUnitCount
data.subUnitCount++
fnScope.data = data
return sc.CreateFunctionSubUnit(fmt.Sprintf("anon_%d", index))
}
func (sc *ScopeChain) CreateFunctionSubUnit(subUnitName string) code.Marker {
fnScope := sc.CurrentFunction()
data := fnScope.data.(ScopeFunction)
name := data.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.scopes[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.scopes[id.scopeID].functionSymbols[id.indexInScope]
}
type SymbolID struct {
symbolKind SymbolKind
scopeID ScopeID
indexInScope int
}
type ScopeKind int
const (
ScopeKindNormal ScopeKind = iota
ScopeKindFunction
ScopeKindLoop
)
type Scope struct {
variableSymbols []Symbol[SymbolVariable]
functionSymbols []Symbol[SymbolFunction]
kind ScopeKind
data any
}
func NewNormalScope() Scope {
return Scope{
variableSymbols: make([]Symbol[SymbolVariable], 0),
functionSymbols: make([]Symbol[SymbolFunction], 0),
kind: ScopeKindNormal,
data: ScopeNormal{},
}
}
func NewFunctionScope(id ScopeID, unit code.Marker) Scope {
return Scope{
variableSymbols: make([]Symbol[SymbolVariable], 0),
functionSymbols: make([]Symbol[SymbolFunction], 0),
kind: ScopeKindFunction,
data: ScopeFunction{
id: id,
unit: unit,
subUnitCount: 0,
},
}
}
type ScopeNormal struct{}
type ScopeFunction struct {
id ScopeID
unit code.Marker
subUnitCount int
}
func (sf ScopeFunction) ID() ScopeID {
return sf.id
}
func (sf ScopeFunction) IsRootScope() bool {
return sf.ID() == ScopeID(0)
}
type ScopeLoop struct {
breakMarker code.Marker
continueMarker code.Marker
}
|
