--- a/doc-src/TutorialI/Recdef/document/simplification.tex Sun Aug 28 19:42:10 2005 +0200
+++ b/doc-src/TutorialI/Recdef/document/simplification.tex Sun Aug 28 19:42:19 2005 +0200
@@ -7,6 +7,7 @@
\endisadelimtheory
%
\isatagtheory
+\isamarkupfalse%
%
\endisatagtheory
{\isafoldtheory}%
@@ -14,7 +15,6 @@
\isadelimtheory
%
\endisadelimtheory
-\isamarkuptrue%
%
\begin{isamarkuptext}%
Once we have proved all the termination conditions, the \isacommand{recdef}
@@ -25,12 +25,12 @@
\index{*if expressions!splitting of}
Let us look at an example:%
\end{isamarkuptext}%
-\isamarkupfalse%
-\isacommand{consts}\ gcd\ {\isacharcolon}{\isacharcolon}\ {\isachardoublequote}nat{\isasymtimes}nat\ {\isasymRightarrow}\ nat{\isachardoublequote}\isanewline
-\isamarkupfalse%
-\isacommand{recdef}\ gcd\ {\isachardoublequote}measure\ {\isacharparenleft}{\isasymlambda}{\isacharparenleft}m{\isacharcomma}n{\isacharparenright}{\isachardot}n{\isacharparenright}{\isachardoublequote}\isanewline
-\ \ {\isachardoublequote}gcd\ {\isacharparenleft}m{\isacharcomma}\ n{\isacharparenright}\ {\isacharequal}\ {\isacharparenleft}if\ n{\isacharequal}{\isadigit{0}}\ then\ m\ else\ gcd{\isacharparenleft}n{\isacharcomma}\ m\ mod\ n{\isacharparenright}{\isacharparenright}{\isachardoublequote}\isamarkuptrue%
-%
+\isamarkuptrue%
+\isacommand{consts}\isamarkupfalse%
+\ gcd\ {\isacharcolon}{\isacharcolon}\ {\isachardoublequoteopen}nat{\isasymtimes}nat\ {\isasymRightarrow}\ nat{\isachardoublequoteclose}\isanewline
+\isacommand{recdef}\isamarkupfalse%
+\ gcd\ {\isachardoublequoteopen}measure\ {\isacharparenleft}{\isasymlambda}{\isacharparenleft}m{\isacharcomma}n{\isacharparenright}{\isachardot}n{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ {\isachardoublequoteopen}gcd\ {\isacharparenleft}m{\isacharcomma}\ n{\isacharparenright}\ {\isacharequal}\ {\isacharparenleft}if\ n{\isacharequal}{\isadigit{0}}\ then\ m\ else\ gcd{\isacharparenleft}n{\isacharcomma}\ m\ mod\ n{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}%
\begin{isamarkuptext}%
\noindent
According to the measure function, the second argument should decrease with
@@ -73,13 +73,13 @@
rather than \isa{if} on the right. In the case of \isa{simplification{\isachardot}gcd} the
following alternative definition suggests itself:%
\end{isamarkuptext}%
-\isamarkupfalse%
-\isacommand{consts}\ gcd{\isadigit{1}}\ {\isacharcolon}{\isacharcolon}\ {\isachardoublequote}nat{\isasymtimes}nat\ {\isasymRightarrow}\ nat{\isachardoublequote}\isanewline
-\isamarkupfalse%
-\isacommand{recdef}\ gcd{\isadigit{1}}\ {\isachardoublequote}measure\ {\isacharparenleft}{\isasymlambda}{\isacharparenleft}m{\isacharcomma}n{\isacharparenright}{\isachardot}n{\isacharparenright}{\isachardoublequote}\isanewline
-\ \ {\isachardoublequote}gcd{\isadigit{1}}\ {\isacharparenleft}m{\isacharcomma}\ {\isadigit{0}}{\isacharparenright}\ {\isacharequal}\ m{\isachardoublequote}\isanewline
-\ \ {\isachardoublequote}gcd{\isadigit{1}}\ {\isacharparenleft}m{\isacharcomma}\ n{\isacharparenright}\ {\isacharequal}\ gcd{\isadigit{1}}{\isacharparenleft}n{\isacharcomma}\ m\ mod\ n{\isacharparenright}{\isachardoublequote}\isamarkuptrue%
-%
+\isamarkuptrue%
+\isacommand{consts}\isamarkupfalse%
+\ gcd{\isadigit{1}}\ {\isacharcolon}{\isacharcolon}\ {\isachardoublequoteopen}nat{\isasymtimes}nat\ {\isasymRightarrow}\ nat{\isachardoublequoteclose}\isanewline
+\isacommand{recdef}\isamarkupfalse%
+\ gcd{\isadigit{1}}\ {\isachardoublequoteopen}measure\ {\isacharparenleft}{\isasymlambda}{\isacharparenleft}m{\isacharcomma}n{\isacharparenright}{\isachardot}n{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ {\isachardoublequoteopen}gcd{\isadigit{1}}\ {\isacharparenleft}m{\isacharcomma}\ {\isadigit{0}}{\isacharparenright}\ {\isacharequal}\ m{\isachardoublequoteclose}\isanewline
+\ \ {\isachardoublequoteopen}gcd{\isadigit{1}}\ {\isacharparenleft}m{\isacharcomma}\ n{\isacharparenright}\ {\isacharequal}\ gcd{\isadigit{1}}{\isacharparenleft}n{\isacharcomma}\ m\ mod\ n{\isacharparenright}{\isachardoublequoteclose}%
\begin{isamarkuptext}%
\noindent
The order of equations is important: it hides the side condition
@@ -89,12 +89,12 @@
A simple alternative is to replace \isa{if} by \isa{case},
which is also available for \isa{bool} and is not split automatically:%
\end{isamarkuptext}%
-\isamarkupfalse%
-\isacommand{consts}\ gcd{\isadigit{2}}\ {\isacharcolon}{\isacharcolon}\ {\isachardoublequote}nat{\isasymtimes}nat\ {\isasymRightarrow}\ nat{\isachardoublequote}\isanewline
-\isamarkupfalse%
-\isacommand{recdef}\ gcd{\isadigit{2}}\ {\isachardoublequote}measure\ {\isacharparenleft}{\isasymlambda}{\isacharparenleft}m{\isacharcomma}n{\isacharparenright}{\isachardot}n{\isacharparenright}{\isachardoublequote}\isanewline
-\ \ {\isachardoublequote}gcd{\isadigit{2}}{\isacharparenleft}m{\isacharcomma}n{\isacharparenright}\ {\isacharequal}\ {\isacharparenleft}case\ n{\isacharequal}{\isadigit{0}}\ of\ True\ {\isasymRightarrow}\ m\ {\isacharbar}\ False\ {\isasymRightarrow}\ gcd{\isadigit{2}}{\isacharparenleft}n{\isacharcomma}m\ mod\ n{\isacharparenright}{\isacharparenright}{\isachardoublequote}\isamarkuptrue%
-%
+\isamarkuptrue%
+\isacommand{consts}\isamarkupfalse%
+\ gcd{\isadigit{2}}\ {\isacharcolon}{\isacharcolon}\ {\isachardoublequoteopen}nat{\isasymtimes}nat\ {\isasymRightarrow}\ nat{\isachardoublequoteclose}\isanewline
+\isacommand{recdef}\isamarkupfalse%
+\ gcd{\isadigit{2}}\ {\isachardoublequoteopen}measure\ {\isacharparenleft}{\isasymlambda}{\isacharparenleft}m{\isacharcomma}n{\isacharparenright}{\isachardot}n{\isacharparenright}{\isachardoublequoteclose}\isanewline
+\ \ {\isachardoublequoteopen}gcd{\isadigit{2}}{\isacharparenleft}m{\isacharcomma}n{\isacharparenright}\ {\isacharequal}\ {\isacharparenleft}case\ n{\isacharequal}{\isadigit{0}}\ of\ True\ {\isasymRightarrow}\ m\ {\isacharbar}\ False\ {\isasymRightarrow}\ gcd{\isadigit{2}}{\isacharparenleft}n{\isacharcomma}m\ mod\ n{\isacharparenright}{\isacharparenright}{\isachardoublequoteclose}%
\begin{isamarkuptext}%
\noindent
This is probably the neatest solution next to pattern matching, and it is
@@ -104,18 +104,19 @@
derived conditional ones. For \isa{simplification{\isachardot}gcd} it means we have to prove
these lemmas:%
\end{isamarkuptext}%
-\isamarkupfalse%
-\isacommand{lemma}\ {\isacharbrackleft}simp{\isacharbrackright}{\isacharcolon}\ {\isachardoublequote}gcd\ {\isacharparenleft}m{\isacharcomma}\ {\isadigit{0}}{\isacharparenright}\ {\isacharequal}\ m{\isachardoublequote}\isanewline
+\isamarkuptrue%
+\isacommand{lemma}\isamarkupfalse%
+\ {\isacharbrackleft}simp{\isacharbrackright}{\isacharcolon}\ {\isachardoublequoteopen}gcd\ {\isacharparenleft}m{\isacharcomma}\ {\isadigit{0}}{\isacharparenright}\ {\isacharequal}\ m{\isachardoublequoteclose}\isanewline
%
\isadelimproof
%
\endisadelimproof
%
\isatagproof
-\isamarkupfalse%
-\isacommand{apply}{\isacharparenleft}simp{\isacharparenright}\isanewline
-\isamarkupfalse%
-\isacommand{done}%
+\isacommand{apply}\isamarkupfalse%
+{\isacharparenleft}simp{\isacharparenright}\isanewline
+\isacommand{done}\isamarkupfalse%
+%
\endisatagproof
{\isafoldproof}%
%
@@ -124,39 +125,40 @@
%
\endisadelimproof
\isanewline
-\isamarkupfalse%
-\isacommand{lemma}\ {\isacharbrackleft}simp{\isacharbrackright}{\isacharcolon}\ {\isachardoublequote}n\ {\isasymnoteq}\ {\isadigit{0}}\ {\isasymLongrightarrow}\ gcd{\isacharparenleft}m{\isacharcomma}\ n{\isacharparenright}\ {\isacharequal}\ gcd{\isacharparenleft}n{\isacharcomma}\ m\ mod\ n{\isacharparenright}{\isachardoublequote}\isanewline
+\isacommand{lemma}\isamarkupfalse%
+\ {\isacharbrackleft}simp{\isacharbrackright}{\isacharcolon}\ {\isachardoublequoteopen}n\ {\isasymnoteq}\ {\isadigit{0}}\ {\isasymLongrightarrow}\ gcd{\isacharparenleft}m{\isacharcomma}\ n{\isacharparenright}\ {\isacharequal}\ gcd{\isacharparenleft}n{\isacharcomma}\ m\ mod\ n{\isacharparenright}{\isachardoublequoteclose}\isanewline
%
\isadelimproof
%
\endisadelimproof
%
\isatagproof
-\isamarkupfalse%
-\isacommand{apply}{\isacharparenleft}simp{\isacharparenright}\isanewline
-\isamarkupfalse%
-\isacommand{done}%
+\isacommand{apply}\isamarkupfalse%
+{\isacharparenleft}simp{\isacharparenright}\isanewline
+\isacommand{done}\isamarkupfalse%
+%
\endisatagproof
{\isafoldproof}%
%
\isadelimproof
%
\endisadelimproof
-\isamarkuptrue%
%
\begin{isamarkuptext}%
\noindent
Simplification terminates for these proofs because the condition of the \isa{if} simplifies to \isa{True} or \isa{False}.
Now we can disable the original simplification rule:%
\end{isamarkuptext}%
-\isamarkupfalse%
-\isacommand{declare}\ gcd{\isachardot}simps\ {\isacharbrackleft}simp\ del{\isacharbrackright}\isanewline
+\isamarkuptrue%
+\isacommand{declare}\isamarkupfalse%
+\ gcd{\isachardot}simps\ {\isacharbrackleft}simp\ del{\isacharbrackright}\isanewline
%
\isadelimtheory
%
\endisadelimtheory
%
\isatagtheory
+\isamarkupfalse%
%
\endisatagtheory
{\isafoldtheory}%