ref: 7635c9c15d25fce6b392f9899a68a36cdd7c06c4
parent: 412fcca30891a7ef374ef751cab950ef44df0d8a
author: henesy <henesy.dev@gmail.com>
date: Thu Feb 28 07:48:48 EST 2019
add note about pete vnc ;; source, but no explanation for switch
--- a/README.md
+++ b/README.md
@@ -8,6 +8,8 @@
Examples are composed in acme(1) which allows you to right click these strings to jump to the relevant source lines.
+If you'd like to try Inferno without installing, I recommend trying Pete's on-demand VNC: http://tryinferno.reverso.be/
+
The `;` rune indicates a command to be run from the Inferno sh(1) shell.
## Building
--- /dev/null
+++ b/Switch/README.md
@@ -1,0 +1,46 @@
+# Switch
+
+Limbo does not have a verbatim `switch` statement. Rather, it has a statement named `case` which is analogous, but not identical to C's switch-case construct.
+
+Limbo case statements break by default and accept range matching operations involving the `or` and `to` keywords.
+
+Note: A break or continue followed by a label causes a break out of, or the next iteration of, the enclosing construct that is labeled with the same label.
+
+## Source
+
+### switch.b:16,31
+
+
+
+### switch.b:33,42
+
+
+
+### switch.b:44,51
+
+
+
+### switch.b:53,60
+
+
+
+### switch.b:62,69
+
+
+
+## Demo
+
+ ; limbo switch.b
+ ; switch
+ Even
+ Odd
+ i's value: 9
+ Valid hex
+ Quack!
+ This is binary
+ Neither 4 nor 7
+ ;
+
+## Exercises
+
+- Try commenting out the `break` and/or `continue` keywords in the first switch, how does the behavior change?
--- /dev/null
+++ b/Switch/switch.b
@@ -1,0 +1,72 @@
+implement Switch;
+
+include "sys.m";
+include "draw.m";
+
+sys: Sys;
+print, FD: import sys;
+
+Switch: module {+ init: fn(nil: ref Draw->Context, nil: list of string);
+};
+
+init(nil: ref Draw->Context, nil: list of string) {+ sys = load Sys Sys->PATH;
+
+ i := 10;
+
+ # The label labelling the enclosing construct
+ loop:
+
+ for(; i >= 0; i--)
+ case i {+ 0 or 2 or 4 or 6 or 8 or 10 =>
+ print("Even\n");+ continue loop;
+ * =>
+ print("Odd\n");+ break loop;
+ }
+
+ print("i's value: %d\n", i);+
+ c := 'c';
+
+ case c {+ 'a' to 'f' =>
+ print("Valid hex\n");+ 'C' =>
+ print("The letter 'C'\n");+ * =>
+ print("The default\n");+ }
+
+ str := "ducks";
+
+ case str {+ "ducks" =>
+ print("Quack!\n");+ "" =>
+ print("Nil string\n");+ }
+
+ n := 1;
+
+ case n {+ 0 or 1 =>
+ print("This is binary\n");+ * =>
+ print("This is non-binary\n");+ }
+
+ f := big 6;
+
+ case f {+ big 4 => print("The number 4\n");+ big 5 => print("The number 7\n");+ * =>
+ print("Neither 4 nor 7\n");+ }
+
+ exit;
+}