pkg/tool/os: add tasks for environment variables
These are implemented as tasks as they are state
altering and may yield different results on repeated
calls.
Also:
- Remove usage of package errors for pkgs.
- Updated go-cmp
- Fix bug in dependency analysis where default
values could cause a dependency to be concrete
prematurely.
Issue #159
Change-Id: I517eb6892cbeff538c806a822510ffce5dcb31b0
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/4461
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>
diff --git a/pkg/tool/os/os.cue b/pkg/tool/os/os.cue
new file mode 100644
index 0000000..d7e4322
--- /dev/null
+++ b/pkg/tool/os/os.cue
@@ -0,0 +1,56 @@
+// Copyright 2019 The 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 os
+
+// A Value are all possible values allowed in flags.
+// A null value unsets an environment variable.
+Value :: bool | number | *string | null
+
+// Name indicates a valid flag name.
+Name :: !="" & !~"^[$]"
+
+// Setenv defines a set of command line flags, the values of which will be set
+// at run time. The doc comment of the flag is presented to the user in help.
+//
+// To define a shorthand, define the shorthand as a new flag referring to
+// the flag of which it is a shorthand.
+Setenv: {
+ $id: "tool/os.Setenv"
+
+ [Name]: Value
+}
+
+// Getenv gets and parses the specific command line variables.
+Getenv: {
+ $id: "tool/os.Getenv"
+
+ [Name]: Value
+}
+
+// Environ populates a struct with all environment variables.
+Environ: {
+ $id: "tool/os.Environ"
+
+ // A map of all populated values.
+ // Individual entries may be specified ahead of time to enable
+ // validation and parsing. Values that are marked as required
+ // will fail the task if they are not found.
+ [Name]: Value
+}
+
+// Clearenv clears all environment variables.
+Clearenv: {
+ $id: "tool/os.Clearenv"
+}
