Add var subcommand

README.md

@@ -19,6 +19,12 @@ can get you up and running in a hurry.
 is cli version tmux gt 3.2 && echo 🥳 || echo 😢
 ```
 
+### Is Neovim the Default Editor?
+
+```bash
+is var EDITOR set && is var EDITOR eq nvim
+```
+
 ### Is this the target Operating System?
 
 ```bash
@@ -755,6 +761,17 @@ This is useful for scripts where we want to install via `sudo`, but we don't
 want the script to be interactive. That means we can skip installing things
 that require `sudo` and handle them in some other place.
 
+### var
+
+Check if environment variables are set, unset or contain a specific value.
+
+```bash
+is var EDITOR set && is var EDITOR like vim
+```
+
+`set` and `unset` don't require arguments, but the other comparison operators
+(eq|ne|gt|gte|in|like|lt|lte|unlike) do.
+
 ### known
 
 Prints known information about a resource to `STDOUT`. Returns `0` on success
@@ -972,6 +989,9 @@ Commands:
   user [<sudoer>]
     Info about current user. e.g. "is user sudoer"
 
+  var <name> <op> [<val>]
+    Check environment variables. e.g. "is var EDITOR eq nvim"
+
   install-completions
     install shell completions. e.g. "is install-completions" and then run the
     command which is printed to your terminal to get completion in your current

api.go

@@ -1,6 +1,10 @@
 // package main contains the api for the CLI
 package main
 
+import (
+	"fmt"
+)
+
 type AgeCmp struct {
 	Name string `arg:"" required:"" help:"[name of command or path to command]"`
 	Op   string `arg:"" required:"" enum:"gt,lt" help:"[gt|lt]"`
@@ -68,6 +72,22 @@ type UserCmd struct {
 	Sudoer string `arg:"" required:"" default:"sudoer" enum:"sudoer" help:"is current user a passwordless sudoer. e.g. \"is user sudoer\""`
 }
 
+// VarCmd type is configuration for environment variable checks.
+//
+//nolint:lll
+type VarCmd struct {
+	Name string `arg:"" required:""`
+	Op   string `arg:"" required:"" enum:"set,unset,eq,ne,gt,gte,in,lt,lte,like,unlike" help:"[set|unset|eq|ne|gt|gte|in|like|lt|lte|unlike]"`
+	Val  string `arg:"" optional:""`
+}
+
+func (r *VarCmd) Validate() error {
+	if r.Op != "set" && r.Op != "unset" && r.Val == "" {
+		return fmt.Errorf("missing required argument: val")
+	}
+	return nil
+}
+
 type KnownCLI struct {
 	Attr string `arg:"" name:"attribute" required:"" enum:"version"`
 	Name string `arg:"" required:""`

main.go

@@ -20,6 +20,7 @@ func main() {
 		OS      OSCmd            `cmd:"" help:"Check OS attributes. e.g. \"is os name eq darwin\""`
 		There   ThereCmd         `cmd:"" help:"Check if command exists. e.g. \"is there git\""`
 		User    UserCmd          `cmd:"" help:"Info about current user. e.g. \"is user sudoer\""`
+		Var     VarCmd           `cmd:"" help:"Check environment variables. e.g. \"is var EDITOR eq nvim\""`
 		Version kong.VersionFlag `help:"Print version to screen"`
 
 		InstallCompletions kongplete.InstallCompletions `cmd:"" help:"install shell completions. e.g. \"is install-completions\" and then run the command which is printed to your terminal to get completion in your current session. add the command to a .bashrc or similar to get completion across all sessions."` //nolint:lll

test/var.bats

@@ -0,0 +1,56 @@
+#!/usr/bin/env bats
+
+bats_require_minimum_version 1.5.0
+
+setup() {
+  export TEST_VAR="nvim"
+}
+
+teardown() {
+  unset TEST_VAR
+}
+
+@test "is var TEST_VAR set" {
+  run ./is var TEST_VAR set
+  [ "$status" -eq 0 ]
+}
+
+@test "is var TEST_VAR unset" {
+  run ./is var TEST_VAR unset
+  [ "$status" -eq 1 ]
+}
+
+@test "is var TEST_VAR eq nvim" {
+  run ./is var TEST_VAR eq nvim
+  [ "$status" -eq 0 ]
+}
+
+@test "is var TEST_VAR eq vim" {
+  run ./is var TEST_VAR eq vim
+  [ "$status" -eq 1 ]
+}
+
+@test "is var TEST_VAR gt 1" {
+  run ./is var TEST_VAR gt 1
+  [ "$status" -eq 1 ]
+}
+
+@test "is var TEST_VAR like nv.*" {
+  run ./is var TEST_VAR like "nv.*"
+  [ "$status" -eq 0 ]
+}
+
+@test "is var TEST_VAR unlike nv.*" {
+  run ./is var TEST_VAR unlike "nv.*"
+  [ "$status" -eq 1 ]
+}
+
+@test "is var NON_EXISTENT_VAR set" {
+  run ./is var NON_EXISTENT_VAR set
+  [ "$status" -eq 1 ]
+}
+
+@test "is var NON_EXISTENT_VAR unset" {
+  run ./is var NON_EXISTENT_VAR unset
+  [ "$status" -eq 0 ]
+}

var.go

@@ -0,0 +1,35 @@
+// This file handles environment variable parsing
+package main
+
+import (
+	"errors"
+	"os"
+
+	"github.com/oalders/is/compare"
+	"github.com/oalders/is/types"
+)
+
+func (r *VarCmd) Run(ctx *types.Context) error {
+	ctx.Success = false
+
+	switch r.Op {
+	case "set":
+		_, exists := os.LookupEnv(r.Name)
+		if exists {
+			ctx.Success = true
+		}
+		return nil
+	case "unset":
+		_, exists := os.LookupEnv(r.Name)
+		if !exists {
+			ctx.Success = true
+		}
+		return nil
+	default:
+		val, exists := os.LookupEnv(r.Name)
+		if !exists {
+			return errors.New("environment variable not set")
+		}
+		return compare.Optimistic(ctx, r.Op, val, r.Val)
+	}
+}