cli: add "amber exec" command for executing one-liners (amberframewor…

…k#352)

src/amber/cli/commands/exec.cr

@@ -0,0 +1,44 @@
+require "cli"
+
+module Amber::CLI
+  class MainCommand < ::Cli::Supercommand
+    command "e", aliased: "exec"
+
+    class Exec < ::Cli::Command
+      command_name "exec"
+
+      class Options
+        arg "code", desc: "Crystal code or .cr file to execute within the application scope", required: false, default: nil
+        string ["-e", "--editor"], desc: "Prefered editor: [vim, nano, pico, etc], only used when no code or .cr file is specified", default: "vim"
+        bool ["-p", "--persist"], desc: "Persist the code across invocations of 'amber exec'"
+      end
+
+      class Help
+        caption "# It runs Crystal code within the application scope"
+      end
+
+      def run
+        result = ""
+        if args.size > 0 && args.code
+          if args.code.ends_with?(".cr") && File.exists?(args.code)
+            result = `crystal eval 'require "../config/*"; require "./#{args.code}"'`
+          else
+            result = `crystal eval 'require "../config/*"; puts (#{args.code}).inspect'`
+          end
+        else
+          system("#{options.editor} .amber_exec.cr")
+          if File.exists?(".amber_exec.cr")
+            result = `crystal eval 'require "../config/*"; require "./.amber_exec.cr"'`
+            File.delete(".amber_exec.cr") unless options.persist?
+          end
+        end
+        if result.includes?("Error in line 1:") &&
+           result.includes?("while requiring \"../config/*\": can't find file '../config/*' relative to '.'")
+          puts "error: 'amber exec' can only be used within the root of a valid amber project"
+        else
+          puts result
+        end
+      end
+    end
+  end
+end