Mercurial > urweb
comparison doc/manual.tex @ 2125:15d46eb02570
Document hexadecimal literals
| author | Adam Chlipala <adam@chlipala.net> |
|---|---|
| date | Thu, 05 Mar 2015 15:05:53 -0500 |
| parents | 1218daa14279 |
| children | 752e5efe9da9 |
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| 2124:f3c24e6790ba | 2125:15d46eb02570 |
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| 632 | 632 |
| 633 It is possible to write a $\mt{let}$ expression with its constituents in reverse order, along the lines of Haskell's \cd{where}. An expression $\mt{let} \; e \; \mt{where} \; ed^* \; \mt{end}$ desugars to $\mt{let} \; ed^* \; \mt{in} \; e \; \mt{end}$. | 633 It is possible to write a $\mt{let}$ expression with its constituents in reverse order, along the lines of Haskell's \cd{where}. An expression $\mt{let} \; e \; \mt{where} \; ed^* \; \mt{end}$ desugars to $\mt{let} \; ed^* \; \mt{in} \; e \; \mt{end}$. |
| 634 | 634 |
| 635 Ur/Web also includes a few more infix operators: $f \; \texttt{<|} \; x$ desugars to $f \; x$, $x \; \texttt{|>} \; f$ to $f \; x$, $f \; \texttt{<{}<{}<} \; g$ to $\mt{Top}.\mt{compose} \; f \; g$, and $g \; \texttt{>{}>{}>} \; f$ to $\mt{Top}.\mt{compose} \; f \; g$. (The latter two are doing function composition in the usual way.) Furthermore, any identifier may be changed into an infix operator by placing it between backticks, e.g. a silly way to do addition is $x \; \texttt{`}\mt{plus}\texttt{`} \; y$ instead of $x + y$. | 635 Ur/Web also includes a few more infix operators: $f \; \texttt{<|} \; x$ desugars to $f \; x$, $x \; \texttt{|>} \; f$ to $f \; x$, $f \; \texttt{<{}<{}<} \; g$ to $\mt{Top}.\mt{compose} \; f \; g$, and $g \; \texttt{>{}>{}>} \; f$ to $\mt{Top}.\mt{compose} \; f \; g$. (The latter two are doing function composition in the usual way.) Furthermore, any identifier may be changed into an infix operator by placing it between backticks, e.g. a silly way to do addition is $x \; \texttt{`}\mt{plus}\texttt{`} \; y$ instead of $x + y$. |
| 636 | 636 |
| 637 Hexadecimal integer literals are supported like \texttt{0xDEADBEEF}. Only capital letters are allowed. | |
| 638 | |
| 637 | 639 |
| 638 \section{Static Semantics} | 640 \section{Static Semantics} |
| 639 | 641 |
| 640 In this section, we give a declarative presentation of Ur's typing rules and related judgments. Inference is the subject of the next section; here, we assume that an oracle has filled in all wildcards with concrete values. | 642 In this section, we give a declarative presentation of Ur's typing rules and related judgments. Inference is the subject of the next section; here, we assume that an oracle has filled in all wildcards with concrete values. |
| 641 | 643 |