Add Loop control

[inform-resources.git] / informqr / informqr.md

diff --git a/informqr/informqr.md b/informqr/informqr.md
index e12df8ef2e569a5f453f424ed9918e42b9078151..c43d0c4e1e58877454b3d45b1302fb1cb31086c2 100644 (file)
--- a/informqr/informqr.md
+++ b/informqr/informqr.md
@@ -1,4 +1,4 @@
-o% Inform in four minutes
+% Inform in four minutes
 % Roger Firth <roger@firthworks.com>
 
 A quick reference to the Inform programming language.
@@ -359,4 +359,69 @@ or an explicit return statement:
 To define a dummy standalone routine with N local variables (unless it
 already exists):
 
-    Stub routine N;
\ No newline at end of file
+    Stub routine N;
+
+Flow control
+------------
+
+To execute statements if *expr* is true; optionally, to execute other
+statements if *expr* is false:
+
+    if (expr)
+        statement_block
+    if (expr)
+        statement_block
+    else
+        statement_block
+
+To execute statements depending on the value of *expr*:
+
+    switch (expr) {
+        value: statement; ... statement;
+        value: statement; ... statement;
+        ...
+        default: statement; ... statement;
+        }
+
+where each *value* can be given as:
+
+    constant
+    lo_constant to hi_constant
+    constant,constant, ... constant
+
+Loop control
+------------
+
+To execute statements while *expr* is true:
+
+    while (expr)
+        statement_block
+
+To execute statements until *expr* is true:
+
+    do
+        statement_block
+        until (expr)
+
+To execute statements while a variable changes:
+
+    for (set_var : loop_while_expr : update_var )
+        statement_block
+
+To execute statements for all defined objects:
+
+    objectloop (variable)
+        statement_block
+
+To execute statements for all objects selected by *expr*:
+
+    objectloop (expr_starting_with_variable)
+        statement_block
+
+To jump out of the current innermost loop or switch:
+
+    break;
+
+To immediately start the next iteration of the current loop:
+
+    continue;
\ No newline at end of file