Mercurial > urweb
diff doc/manual.tex @ 1302:d008c4c43a0a
Flex kinds for type-level tuples; ::_ notation
author | Adam Chlipala <adam@chlipala.net> |
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date | Sun, 10 Oct 2010 13:07:38 -0400 |
parents | e3944a8a128a |
children | 3a845f2ce9e9 |
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--- a/doc/manual.tex Thu Sep 30 18:29:59 2010 -0400 +++ b/doc/manual.tex Sun Oct 10 13:07:38 2010 -0400 @@ -495,6 +495,8 @@ 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 $b^+$. +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. + 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. A signature item or declaration $\mt{type} \; x$ or $\mt{type} \; x = \tau$ is elaborated into $\mt{con} \; x :: \mt{Type}$ or $\mt{con} \; x :: \mt{Type} = \tau$, respectively.