Commit 1bf7e350 authored by ravi@bluespec.com's avatar ravi@bluespec.com
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pattern_guard_list_comprehension_footnote

parent da2accf8
......@@ -858,7 +858,9 @@ A {\em guard}\index{guard} has one of the following forms:
\item {\em pattern guards}\index{pattern guard} are of the form "p @<-@ e", where
"p" is a
pattern (see Section~\ref{pattern-matching}) of type "t" and "e" is an
expression type "t". They succeed if the expression "e" matches the pattern "p", and introduce the bindings of the pattern to the environment.
expression type "t"\footnote{Note that the syntax of a pattern guard is the same as that of a generator in a list comprehension.
The minor contextual difference is that, in a list comprehension, a pattern of type "t" goes with an expression of type "@[@t@]@".}.
They succeed if the expression "e" matches the pattern "p", and introduce the bindings of the pattern to the environment.
\item {\em boolean guards}\index{boolean guard} are arbitrary expressions of
type @Bool@. They succeed if the expression evaluates to @True@, and they do not introduce new names to the environment. A boolean guard, "g", is semantically equivalent to the pattern guard "@True <- @g".
\item {\em local bindings} are of the form "@let @decls". They always succeed, and they introduce the names defined in "decls" to the environment.
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