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// Copyright 2020 CUE Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package filetypes
import (
"strings"
"cuelang.org/go/cue/ast"
)
// IsPackage reports whether a command-line argument is a package based on its
// lexical representation alone.
func IsPackage(s string) bool {
switch s {
case ".", "..":
return true
case "", "-":
return false
}
// This goes off the assumption that file names may not have a `:` in their
// name in cue.
// A filename must have an extension or be preceded by a qualifier argument.
// So strings of the form foo/bar:baz, where bar is a valid identifier and
// absolute package
if p := strings.LastIndexByte(s, ':'); p > 0 {
if !ast.IsValidIdent(s[p+1:]) {
return false
}
// For a non-pkg, the part before : may only be lowercase and '+'.
// In addition, a package necessarily must have a slash of some form.
return strings.ContainsAny(s[:p], `/.\`)
}
// Assuming we terminate search for packages once a scoped qualifier is
// found, we know that any file without an extension (except maybe '-')
// is invalid. We can therefore assume it is a package.
// The section may still contain a dot, for instance ./foo/., ./.foo/, or ./foo/...
return strings.TrimLeft(fileExt(s), ".") == ""
// NOTE/TODO: we have not needed to check whether it is an absolute package
// or whether the package starts with a dot. Potentially we could thus relax
// the requirement that packages be dots if it is clear that the package
// name will not interfere with command names in all circumstances.
}
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