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package compiler
import (
"io/ioutil"
"strings"
"github.com/d5/tengo/compiler/ast"
"github.com/d5/tengo/compiler/parser"
"github.com/d5/tengo/objects"
)
func (c *Compiler) compileModule(expr *ast.ImportExpr) (*objects.CompiledFunction, error) {
compiledModule, exists := c.loadCompiledModule(expr.ModuleName)
if exists {
return compiledModule, nil
}
moduleName := expr.ModuleName
// read module source from loader
var moduleSrc []byte
if c.moduleLoader == nil {
// default loader: read from local file
if !strings.HasSuffix(moduleName, ".tengo") {
moduleName += ".tengo"
}
if err := c.checkCyclicImports(expr, moduleName); err != nil {
return nil, err
}
var err error
moduleSrc, err = ioutil.ReadFile(moduleName)
if err != nil {
return nil, c.errorf(expr, "module file read error: %s", err.Error())
}
} else {
if err := c.checkCyclicImports(expr, moduleName); err != nil {
return nil, err
}
var err error
moduleSrc, err = c.moduleLoader(moduleName)
if err != nil {
return nil, err
}
}
compiledModule, err := c.doCompileModule(moduleName, moduleSrc)
if err != nil {
return nil, err
}
c.storeCompiledModule(moduleName, compiledModule)
return compiledModule, nil
}
func (c *Compiler) checkCyclicImports(node ast.Node, moduleName string) error {
if c.moduleName == moduleName {
return c.errorf(node, "cyclic module import: %s", moduleName)
} else if c.parent != nil {
return c.parent.checkCyclicImports(node, moduleName)
}
return nil
}
func (c *Compiler) doCompileModule(moduleName string, src []byte) (*objects.CompiledFunction, error) {
modFile := c.file.Set().AddFile(moduleName, -1, len(src))
p := parser.NewParser(modFile, src, nil)
file, err := p.ParseFile()
if err != nil {
return nil, err
}
symbolTable := NewSymbolTable()
// inherit builtin functions
for idx, fn := range objects.Builtins {
s, _, ok := c.symbolTable.Resolve(fn.Name)
if ok && s.Scope == ScopeBuiltin {
symbolTable.DefineBuiltin(idx, fn.Name)
}
}
// no global scope for the module
symbolTable = symbolTable.Fork(false)
// compile module
moduleCompiler := c.fork(modFile, moduleName, symbolTable)
if err := moduleCompiler.Compile(file); err != nil {
return nil, err
}
// add OpReturn (== export undefined) if export is missing
if !moduleCompiler.lastInstructionIs(OpReturnValue) {
moduleCompiler.emit(nil, OpReturn)
}
compiledFunc := moduleCompiler.Bytecode().MainFunction
compiledFunc.NumLocals = symbolTable.MaxSymbols()
return compiledFunc, nil
}
func (c *Compiler) loadCompiledModule(moduleName string) (mod *objects.CompiledFunction, ok bool) {
if c.parent != nil {
return c.parent.loadCompiledModule(moduleName)
}
mod, ok = c.compiledModules[moduleName]
return
}
func (c *Compiler) storeCompiledModule(moduleName string, module *objects.CompiledFunction) {
if c.parent != nil {
c.parent.storeCompiledModule(moduleName, module)
}
c.compiledModules[moduleName] = module
}
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