diff -r fcff0c66b4f4 -r 08eee994bf99 doc-src/TutorialI/Documents/document/Documents.tex --- a/doc-src/TutorialI/Documents/document/Documents.tex Fri Jan 04 19:19:29 2002 +0100 +++ b/doc-src/TutorialI/Documents/document/Documents.tex Fri Jan 04 19:19:51 2002 +0100 @@ -2,6 +2,130 @@ \begin{isabellebody}% \def\isabellecontext{Documents}% \isamarkupfalse% +% +\isamarkupsection{Concrete syntax \label{sec:concrete-syntax}% +} +\isamarkuptrue% +% +\begin{isamarkuptext}% +Concerning Isabelle's ``inner'' language of simply-typed \isa{{\isasymlambda}}-calculus, the core concept of Isabelle's elaborate infrastructure + for concrete syntax is that of general \emph{mixfix + annotations}\index{mixfix annotations|bold}. Associated with any + kind of name and type declaration, mixfixes give rise both to + grammar productions for the parser and output templates for the + pretty printer. + + In full generality, the whole affair of parser and pretty printer + configuration is rather subtle. Any syntax specifications given by + end-users need to interact properly with the existing setup of + Isabelle/Pure and Isabelle/HOL; see \cite{isabelle-ref} for further + details. It is particularly important to get the precedence of new + syntactic constructs right, avoiding ambiguities with existing + elements. + + \medskip Subsequently we introduce a few simple declaration forms + that already cover the most common situations fairly well.% +\end{isamarkuptext}% +\isamarkuptrue% +% +\isamarkupsubsection{Infixes% +} +\isamarkuptrue% +% +\begin{isamarkuptext}% +Syntax annotations may be included wherever constants are declared + directly or indirectly, including \isacommand{consts}, + \isacommand{constdefs}, or \isacommand{datatype} (for the + constructor operations). Type-constructors may be annotated as + well, although this is less frequently encountered in practice + (\isa{{\isacharasterisk}} and \isa{{\isacharplus}} types may come to mind). + + Infix declarations\index{infix annotations|bold} provide a useful + special case of mixfixes, where users need not care about the full + details of priorities, nesting, spacing, etc. The subsequent + example of the exclusive-or operation on boolean values illustrates + typical infix declarations.% +\end{isamarkuptext}% +\isamarkuptrue% +\isacommand{constdefs}\isanewline +\ \ xor\ {\isacharcolon}{\isacharcolon}\ {\isachardoublequote}bool\ {\isasymRightarrow}\ bool\ {\isasymRightarrow}\ bool{\isachardoublequote}\ \ \ \ {\isacharparenleft}\isakeyword{infixl}\ {\isachardoublequote}{\isacharbrackleft}{\isacharplus}{\isacharbrackright}{\isachardoublequote}\ {\isadigit{6}}{\isadigit{0}}{\isacharparenright}\isanewline +\ \ {\isachardoublequote}A\ {\isacharbrackleft}{\isacharplus}{\isacharbrackright}\ B\ {\isasymequiv}\ {\isacharparenleft}A\ {\isasymand}\ {\isasymnot}\ B{\isacharparenright}\ {\isasymor}\ {\isacharparenleft}{\isasymnot}\ A\ {\isasymand}\ B{\isacharparenright}{\isachardoublequote}\isamarkupfalse% +% +\begin{isamarkuptext}% +Any curried function with at least two arguments may be associated + with infix syntax: \isa{xor\ A\ B} and \isa{A\ {\isacharbrackleft}{\isacharplus}{\isacharbrackright}\ B} refer to + the same expression internally. In partial applications with less + than two operands there is a special notation with \isa{op} prefix: + \isa{xor} without arguments is represented as \isa{op\ {\isacharbrackleft}{\isacharplus}{\isacharbrackright}}; + combined with plain prefix application this turns \isa{xor\ A} + into \isa{op\ {\isacharbrackleft}{\isacharplus}{\isacharbrackright}\ A}. + + \medskip The string \isa{{\isachardoublequote}{\isacharbrackleft}{\isacharplus}{\isacharbrackright}{\isachardoublequote}} in the above declaration + refers to the bit of concrete syntax to represent the operator, + while the number \isa{{\isadigit{6}}{\isadigit{0}}} determines the precedence of the whole + construct. + + As it happens, Isabelle/HOL already spends many popular combinations + of ASCII symbols for its own use, including both \isa{{\isacharplus}} and + \isa{{\isacharplus}{\isacharplus}}. Slightly more awkward combinations like the present + \isa{{\isacharbrackleft}{\isacharplus}{\isacharbrackright}} tend to be available for user extensions. The current + arrangement of inner syntax may be inspected via + \commdx{print\protect\_syntax}, albeit its output is enormous. + + Operator precedence also needs some special considerations. The + admissible range is 0--1000. Very low or high priorities are + basically reserved for the meta-logic. Syntax of Isabelle/HOL + mainly uses the range of 10--100: the equality infix \isa{{\isacharequal}} is + centered at 50, logical connectives (like \isa{{\isasymor}} and \isa{{\isasymand}}) are below 50, and algebraic ones (like \isa{{\isacharplus}} and \isa{{\isacharasterisk}}) above 50. User syntax should strive to coexist with common + HOL forms, or use the mostly unused range 100--900. + + \medskip The keyword \isakeyword{infixl} specifies an operator that + is nested to the \emph{left}: in iterated applications the more + complex expression appears on the left-hand side: \isa{A\ {\isacharbrackleft}{\isacharplus}{\isacharbrackright}\ B\ {\isacharbrackleft}{\isacharplus}{\isacharbrackright}\ C} stands for \isa{{\isacharparenleft}A\ {\isacharbrackleft}{\isacharplus}{\isacharbrackright}\ B{\isacharparenright}\ {\isacharbrackleft}{\isacharplus}{\isacharbrackright}\ C}. Similarly, + \isakeyword{infixr} refers to nesting to the \emph{right}, which + would turn \isa{A\ {\isacharbrackleft}{\isacharplus}{\isacharbrackright}\ B\ {\isacharbrackleft}{\isacharplus}{\isacharbrackright}\ C} into \isa{A\ {\isacharbrackleft}{\isacharplus}{\isacharbrackright}\ {\isacharparenleft}B\ {\isacharbrackleft}{\isacharplus}{\isacharbrackright}\ C{\isacharparenright}}. + In contrast, a \emph{non-oriented} declaration via + \isakeyword{infix} would always demand explicit parentheses. + + Many binary operations observe the associative law, so the exact + grouping does not matter. Nevertheless, formal statements need be + given in a particular format, associativity needs to be treated + explicitly within the logic. Exclusive-or is happens to be + associative, as shown below.% +\end{isamarkuptext}% +\isamarkuptrue% +\isacommand{lemma}\ xor{\isacharunderscore}assoc{\isacharcolon}\ {\isachardoublequote}{\isacharparenleft}A\ {\isacharbrackleft}{\isacharplus}{\isacharbrackright}\ B{\isacharparenright}\ {\isacharbrackleft}{\isacharplus}{\isacharbrackright}\ C\ {\isacharequal}\ A\ {\isacharbrackleft}{\isacharplus}{\isacharbrackright}\ {\isacharparenleft}B\ {\isacharbrackleft}{\isacharplus}{\isacharbrackright}\ C{\isacharparenright}{\isachardoublequote}\isanewline +\ \ \isamarkupfalse% +\isacommand{by}\ {\isacharparenleft}auto\ simp\ add{\isacharcolon}\ xor{\isacharunderscore}def{\isacharparenright}\isamarkupfalse% +% +\begin{isamarkuptext}% +Such rules may be used in simplification to regroup nested + expressions as required. Note that the system would actually print + the above statement as \isa{A\ {\isacharbrackleft}{\isacharplus}{\isacharbrackright}\ B\ {\isacharbrackleft}{\isacharplus}{\isacharbrackright}\ C\ {\isacharequal}\ A\ {\isacharbrackleft}{\isacharplus}{\isacharbrackright}\ {\isacharparenleft}B\ {\isacharbrackleft}{\isacharplus}{\isacharbrackright}\ C{\isacharparenright}} + (due to nesting to the left). We have preferred to give the fully + parenthesized form in the text for clarity.% +\end{isamarkuptext}% +\isamarkuptrue% +\isamarkuptrue% +\isamarkuptrue% +\isamarkupfalse% +\isamarkupfalse% +\isamarkupfalse% +\isamarkupfalse% +\isamarkuptrue% +\isamarkuptrue% +\isamarkupfalse% +\isamarkuptrue% +\isamarkuptrue% +\isamarkuptrue% +\isamarkupfalse% +\isamarkuptrue% +\isamarkuptrue% +\isamarkuptrue% +\isamarkuptrue% +\isamarkuptrue% +\isamarkuptrue% +\isamarkuptrue% \isamarkupfalse% \end{isabellebody}% %%% Local Variables: