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111 lines
2.3 KiB
111 lines
2.3 KiB
package compiler
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import (
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"fmt"
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"github.com/brettlangdon/gython/ast"
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"github.com/brettlangdon/gython/bytecode"
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)
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type Compiler struct {
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nestLevel int
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scopeStack []*Scope
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}
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func NewCompiler() *Compiler {
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return &Compiler{
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nestLevel: 0,
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scopeStack: make([]*Scope, 0),
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}
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}
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func (compiler *Compiler) currentScope() *Scope {
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length := len(compiler.scopeStack)
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if length > 0 {
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return compiler.scopeStack[length-1]
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}
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return nil
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}
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func (compiler *Compiler) enterScope() *Scope {
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scope := NewScope()
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compiler.scopeStack = append(compiler.scopeStack, scope)
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compiler.nestLevel++
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return scope
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}
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func (compiler *Compiler) exitScope() *Scope {
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last := len(compiler.scopeStack) - 1
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scope := compiler.scopeStack[last]
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compiler.scopeStack = compiler.scopeStack[:last]
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compiler.nestLevel--
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return scope
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}
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func (compiler *Compiler) assemble(addNone bool) *bytecode.CodeObject {
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if addNone {
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compiler.addOp(bytecode.LOAD_CONST)
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compiler.addOp(bytecode.RETURN_VALUE)
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}
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codeobject := bytecode.NewCodeObject()
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return codeobject
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}
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func (compiler *Compiler) addOp(op bytecode.Opcode) bool {
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fmt.Println(bytecode.Opnames[op])
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return true
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}
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func (compiler *Compiler) visitExpression(expr ast.Expression) bool {
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switch expr := expr.(type) {
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case *ast.Num:
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compiler.addOp(bytecode.LOAD_CONST)
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case *ast.Name:
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compiler.addOp(bytecode.STORE_NAME)
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default:
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fmt.Println(expr)
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}
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return true
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}
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func (compiler *Compiler) visitStatement(stmt ast.Statement) bool {
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switch stmt := stmt.(type) {
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case *ast.Assign:
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compiler.visitExpression(stmt.Value)
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length := len(stmt.Targets)
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for i := 0; i < length; i++ {
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if i < length-1 {
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compiler.addOp(bytecode.DUP_TOP)
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}
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compiler.visitExpression(stmt.Targets[i])
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}
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}
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return true
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}
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func (compiler *Compiler) compileBody(stmts []ast.Statement) bool {
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// TODO: Check for docstring
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for _, stmt := range stmts {
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compiler.visitStatement(stmt)
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}
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return true
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}
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func (compiler *Compiler) CompileMod(root ast.Mod) *bytecode.CodeObject {
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addNone := true
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compiler.enterScope()
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var codeobject *bytecode.CodeObject
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switch root := root.(type) {
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case *ast.Module:
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if !compiler.compileBody(root.Body) {
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compiler.exitScope()
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return nil
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}
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}
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codeobject = compiler.assemble(addNone)
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compiler.exitScope()
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return codeobject
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}
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