Gecko [ 167.86.127.34 ]

Name	Size	Permission
testdata	[ DIR ]	drwxr-xr-x
api.go	13.6 KB	-rw-r--r--
api_test.go	41.52 KB	-rw-r--r--
assignments.go	8.58 KB	-rw-r--r--
builtins.go	17.25 KB	-rw-r--r--
builtins_test.go	7.54 KB	-rw-r--r--
call.go	13.86 KB	-rw-r--r--
check.go	12.43 KB	-rw-r--r--
check_test.go	8.65 KB	-rw-r--r--
conversions.go	4.86 KB	-rw-r--r--
decl.go	22.25 KB	-rw-r--r--
errors.go	3.14 KB	-rw-r--r--
eval.go	2.92 KB	-rw-r--r--
eval_test.go	7.12 KB	-rw-r--r--
example_test.go	8.77 KB	-rw-r--r--
expr.go	44.32 KB	-rw-r--r--
exprstring.go	4.54 KB	-rw-r--r--
exprstring_test.go	1.76 KB	-rw-r--r--
gccgosizes.go	1016 B	-rw-r--r--
gotype.go	8.4 KB	-rw-r--r--
hilbert_test.go	3.63 KB	-rw-r--r--
initorder.go	8.84 KB	-rw-r--r--
issues_test.go	12.86 KB	-rw-r--r--
labels.go	7.01 KB	-rw-r--r--
lookup.go	13.05 KB	-rw-r--r--
methodset.go	8.38 KB	-rw-r--r--
object.go	14.69 KB	-rw-r--r--
object_test.go	2.82 KB	-rw-r--r--
objset.go	927 B	-rw-r--r--
operand.go	7.46 KB	-rw-r--r--
package.go	2.19 KB	-rw-r--r--
predicates.go	9.01 KB	-rw-r--r--
resolver.go	20.76 KB	-rw-r--r--
resolver_test.go	4.58 KB	-rw-r--r--
return.go	4.23 KB	-rw-r--r--
scope.go	5.48 KB	-rw-r--r--
selection.go	3.99 KB	-rw-r--r--
self_test.go	2.2 KB	-rw-r--r--
sizes.go	6.61 KB	-rw-r--r--
sizes_test.go	2.46 KB	-rw-r--r--
stdlib_test.go	8.32 KB	-rw-r--r--
stmt.go	22.8 KB	-rw-r--r--
token_test.go	1.21 KB	-rw-r--r--
type.go	16.81 KB	-rw-r--r--
typestring.go	7.8 KB	-rw-r--r--
typestring_test.go	6.56 KB	-rw-r--r--
typexpr.go	20.6 KB	-rw-r--r--
universe.go	6.47 KB	-rw-r--r--

Code Editor : eval.go

// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package types

import (
	"fmt"
	"go/ast"
	"go/parser"
	"go/token"
)

// Eval returns the type and, if constant, the value for the
// expression expr, evaluated at position pos of package pkg,
// which must have been derived from type-checking an AST with
// complete position information relative to the provided file
// set.
//
// The meaning of the parameters fset, pkg, and pos is the
// same as in CheckExpr. An error is returned if expr cannot
// be parsed successfully, or the resulting expr AST cannot be
// type-checked.
func Eval(fset *token.FileSet, pkg *Package, pos token.Pos, expr string) (_ TypeAndValue, err error) {
	// parse expressions
	node, err := parser.ParseExprFrom(fset, "eval", expr, 0)
	if err != nil {
		return TypeAndValue{}, err
	}

info := &Info{
		Types: make(map[ast.Expr]TypeAndValue),
	}
	err = CheckExpr(fset, pkg, pos, node, info)
	return info.Types[node], err
}

// CheckExpr type checks the expression expr as if it had appeared at
// position pos of package pkg. Type information about the expression
// is recorded in info.
//
// If pkg == nil, the Universe scope is used and the provided
// position pos is ignored. If pkg != nil, and pos is invalid,
// the package scope is used. Otherwise, pos must belong to the
// package.
//
// An error is returned if pos is not within the package or
// if the node cannot be type-checked.
//
// Note: Eval and CheckExpr should not be used instead of running Check
// to compute types and values, but in addition to Check, as these
// functions ignore the context in which an expression is used (e.g., an
// assignment). Thus, top-level untyped constants will return an
// untyped type rather then the respective context-specific type.
//
func CheckExpr(fset *token.FileSet, pkg *Package, pos token.Pos, expr ast.Expr, info *Info) (err error) {
	// determine scope
	var scope *Scope
	if pkg == nil {
		scope = Universe
		pos = token.NoPos
	} else if !pos.IsValid() {
		scope = pkg.scope
	} else {
		// The package scope extent (position information) may be
		// incorrect (files spread across a wide range of fset
		// positions) - ignore it and just consider its children
		// (file scopes).
		for _, fscope := range pkg.scope.children {
			if scope = fscope.Innermost(pos); scope != nil {
				break
			}
		}
		if scope == nil || debug {
			s := scope
			for s != nil && s != pkg.scope {
				s = s.parent
			}
			// s == nil || s == pkg.scope
			if s == nil {
				return fmt.Errorf("no position %s found in package %s", fset.Position(pos), pkg.name)
			}
		}
	}

// initialize checker
	check := NewChecker(nil, fset, pkg, info)
	check.scope = scope
	check.pos = pos
	defer check.handleBailout(&err)

// evaluate node
	var x operand
	check.rawExpr(&x, expr, nil)
	check.processDelayed(0) // incl. all functions
	check.recordUntyped()

return nil
}

${this.title}

Code Editor : eval.go