langs a-z

Task/Menu/UNIX-Shell/menu-1.sh

@@ -0,0 +1,19 @@
+# choose 'choice 1' 'choice 2' ...
+#   Prints menu to standard error. Prompts with PS3.
+#   Reads REPLY from standard input. Sets CHOICE.
+choose() {
+    CHOICE=                     # Default CHOICE is empty string.
+    [[ $# -gt 0 ]] || return    # Return if "$@" is empty.
+    select CHOICE; do           # Select from "$@".
+        if [[ -n $CHOICE ]]; then
+            break
+        else
+            echo Invalid choice.
+        fi
+    done
+}
+
+PS3='Which is from the three pigs: '
+choose 'fee fie' 'huff and puff' 'mirror mirror' 'tick tock'
+[[ -n $CHOICE ]] && echo You chose: $CHOICE
+[[ -z $CHOICE ]] && echo No input.

Task/Menu/UNIX-Shell/menu-2.sh

@@ -0,0 +1,54 @@
+# choose 'choice 1' 'choice 2' ...
+#   Prints menu to standard error. Prompts with $prompt.
+#   Returns choice. If no input, returns empty list.
+fn choose args {
+	# If args are empty, return empty list.
+	~ $#args 0 && return
+
+	# Echo to standard error.
+	let (reply =; choice =; fn-menu =; fn-ch =) >[1=2] {
+		fn-menu = {
+			# Show menu.
+			let (i = 1) for (c = $args) {
+				echo $i') '$c
+				i = `{expr $i + 1}
+			}
+		}
+		fn-ch = {
+			# Set choice = $args($reply), but ignore error
+			# if $reply is not a valid index.
+			choice = <={catch @ e {result} {
+				result $args($reply)
+			}}
+		}
+
+		menu
+		forever {
+			# Show prompt, read reply.
+			echo -n $prompt
+			reply = <={%read}
+
+			# If no input, return empty list.
+			~ $#reply 0 && return
+
+			# Parse reply and return choice.
+			reply = <={%split \ \t\n $reply}
+			if {~ $#reply 0} {
+				# Empty reply: show menu again.
+				menu
+			} {~ $#reply 1 && ch; ~ $#choice 1} {
+				return $choice
+			} {
+				echo Invalid choice.
+			}
+		}
+	}
+}
+
+let (choice = <={
+	local (prompt = 'Which is from the three pigs: ')
+		choose 'fee fie' 'huff and puff' 'mirror mirror' 'tick tock'
+}) {
+	~ $#choice 1 && echo You chose: $choice
+	~ $#choice 0 && echo No input.
+}