1 files changed, 8 insertions, 0 deletions
diff --git a/doc/expr.n b/doc/expr.n
index 69f6399..2c2742c 100644
--- a/doc/expr.n
+++ b/doc/expr.n
@@ -41,6 +41,12 @@ When an expression evaluates to an integer, the value is the decimal form of
 the integer, and when an expression evaluates to a floating-point number, the
 value is the form produced by the \fB%g\fR format specifier of Tcl's
 \fBformat\fR command.
+.PP
+.VS "TIP 582"
+You can use \fB#\fR at any point in the expression (except inside double
+quotes or braces) to start a comment. Comments last to the end of the line or
+the end of the expression, whichever comes first.
+.VE "TIP 582"
 .SS OPERANDS
 .PP
 An expression consists of a combination of operands, operators, parentheses and
@@ -487,7 +493,9 @@ value of true:
 .PP
 .CS
 set isTrue [\fBexpr\fR {
+    # Does the environment variable exist, and...
     [info exists ::env(SOME_ENV_VAR)] &&
+    # ...does it contain a proper true value?
     [string is true -strict $::env(SOME_ENV_VAR)]
 }]
 .CE