Add help topic for variables

Fixes #60

Cargo.lock

@@ -2944,7 +2944,7 @@ dependencies = [
 
 [[package]]
 name = "tenebrous-dicebot"
-version = "0.13.1"
+version = "0.13.2"
 dependencies = [
  "async-trait",
  "barrel",

dicebot/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "tenebrous-dicebot"
-version = "0.13.1"
+version = "0.13.2"
 rust-version = "1.68"
 authors = ["projectmoon <projectmoon@agnos.is>", "Taylor C. Richberger <taywee@gmx.com>"]
 edition = "2018"

dicebot/src/help.rs

@@ -6,6 +6,9 @@ pub fn parse_help_topic(input: &str) -> Option<HelpTopic> {
         "dicepool" => Some(HelpTopic::DicePool),
         "dice" => Some(HelpTopic::RollingDice),
         "cthulhu" => Some(HelpTopic::Cthulhu),
+        "variables" => Some(HelpTopic::Variables),
+        "var" => Some(HelpTopic::Variables),
+        "variable" => Some(HelpTopic::Variables),
         "" => Some(HelpTopic::General),
         _ => None,
     }
@@ -16,6 +19,7 @@ pub enum HelpTopic {
     DicePool,
     Cthulhu,
     RollingDice,
+    Variables,
     General,
 }
 
@@ -101,6 +105,34 @@ Note: If !cthadv is given a variable, and the roll is successful, it will
 update the variable with the new skill.
 "};
 
+const VARIABLES_HELP: &'static str = indoc! {"
+Variables
+
+Commands: !get, !set, !variables
+
+Manage variables that can be substituted into roll commands.
+
+Examples: !get myvar, !set myvar 10
+
+!get <variable> = show variable of the given name
+!set <variable> <num> = set a variable to a number
+
+The !variables command will list all variables for the room. The
+variables command cna be used in a secure room to avoid spamming the
+actual room that the variable is set in.
+
+Variable names can be used in all types of dice rolls:
+
+!pool myvar + 3
+!roll myvar
+
+There are some limitations on variables: they cannot themselves be
+dice expressions (i.e. can only be numbers), and they must be uniquely
+parseable in an expression (i.e 'myvard6' does not work for the !roll
+command).
+
+"};
+
 const GENERAL_HELP: &'static str = indoc! {"
 General Help
 
@@ -117,6 +149,7 @@ impl HelpTopic {
             HelpTopic::DicePool => DICEPOOL_HELP,
             HelpTopic::Cthulhu => CTHULHU_HELP,
             HelpTopic::RollingDice => DICE_HELP,
+            HelpTopic::Variables => VARIABLES_HELP,
             HelpTopic::General => GENERAL_HELP,
         }
     }