Mercurial > urweb
diff doc/manual.tex @ 1574:644558d9c756
Extend and document 'con' syntax with arguments
author | Adam Chlipala <adam@chlipala.net> |
---|---|
date | Sat, 15 Oct 2011 10:05:13 -0400 |
parents | 34364e383bed |
children | 7d2aa0ddc531 |
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--- a/doc/manual.tex Sat Oct 15 09:04:41 2011 -0400 +++ b/doc/manual.tex Sat Oct 15 10:05:13 2011 -0400 @@ -380,7 +380,7 @@ &&& \{\kappa\} & \textrm{type-level records} \\ &&& (\kappa\times^+) & \textrm{type-level tuples} \\ &&& X & \textrm{variable} \\ - &&& X \longrightarrow k & \textrm{kind-polymorphic type-level function} \\ + &&& X \longrightarrow \kappa & \textrm{kind-polymorphic type-level function} \\ &&& \_\_ & \textrm{wildcard} \\ &&& (\kappa) & \textrm{explicit precedence} \\ \end{array}$$ @@ -549,6 +549,8 @@ In general, several adjacent $\lambda$ forms may be combined into one, and kind and type annotations may be omitted, in which case they are implicitly included as wildcards. More formally, for constructor-level abstractions, we can define a new non-terminal $b ::= x \mid (x :: \kappa) \mid X$ and allow composite abstractions of the form $\lambda b^+ \Rightarrow c$, elaborating into the obvious sequence of one core $\lambda$ per element of $b^+$. +Further, the signature item or declaration syntax $\mt{con} \; x \; b^+ = c$ is shorthand for wrapping of the appropriate $\lambda$s around the righthand side $c$. The $b$ elements may not include $X$, and there may also be an optional $:: \kappa$ before the $=$. + In some contexts, the parser isn't happy with token sequences like $x :: \_$, to indicate a constructor variable of wildcard kind. In such cases, write the second two tokens as $::\hspace{-.05in}\_$, with no intervening spaces. Analogous syntax $:::\hspace{-.05in}\_$ is available for implicit constructor arguments. For any signature item or declaration that defines some entity to be equal to $A$ with classification annotation $B$ (e.g., $\mt{val} \; x : B = A$), $B$ and the preceding colon (or similar punctuation) may be omitted, in which case it is filled in as a wildcard.