tame/core/vector/list.xml

189 lines
6.5 KiB
XML

<?xml version="1.0" encoding="ISO-8859-1"?>
<package xmlns="http://www.lovullo.com/rater"
xmlns:c="http://www.lovullo.com/calc"
xmlns:t="http://www.lovullo.com/rater/apply-template"
core="true"
desc="Treating vectors as lists">
<import package="../base" />
<!--
This abstraction relieves the developer of one of the most common
lisp-style recursions: recursing over a set's cdr until empty.
This template recurses and, as such, should only be used within functions.
-->
<template name="_cons-until-empty_" desc="Generate empty base case for functions that recurse on cdrs of sets">
<param name="@values@" desc="Body" />
<param name="@set@" desc="Set to operate on" />
<param name="@car@" desc="Variable in which to store car of the set">
<text>__car</text>
</param>
<param name="@cdr@" desc="Variable in which to store the cdr of the set">
<text>__cdr</text>
</param>
<param name="@base@" desc="Base set to return (otherwise an empty set)" />
<param name="@glance@" desc="Glance at (but do nothing with) this value; recurse without action" />
<!-- intended for use by merge-until-empty to reduce duplicate code; not to
be set via direct template applications -->
<param name="@merge@" desc="Perform merge instead of cons; system-use only" />
<c:let>
<c:values>
<!-- TODO: it'd be nice if the DSL made values unique for us, unless
they're used, to prevent potential conflicts with template callers
-->
<c:value name="__valn" type="integer" desc="Number of values">
<c:length-of>
<c:value-of name="@set@" />
</c:length-of>
</c:value>
</c:values>
<c:cases>
<c:case>
<c:when name="__valn">
<c:eq>
<c:const value="0" type="integer" desc="When there are no more elements in the set" />
</c:eq>
</c:when>
<!-- if a base set was provided, return that; otherwise, return an empty set -->
<if name="@base@">
<c:value-of name="@base@" />
</if>
<unless name="@base@">
<!-- return an empty set -->
<c:set />
</unless>
</c:case>
<c:otherwise>
<c:let>
<c:values>
<c:value name="@car@" type="float" desc="Car of set">
<c:car>
<c:value-of name="@set@" />
</c:car>
</c:value>
<c:value name="@cdr@" type="float" desc="Cdr of set">
<c:cdr>
<c:value-of name="@set@" />
</c:cdr>
</c:value>
</c:values>
<!-- this case statement will be optimized away if we have no
@glance@ value -->
<c:cases>
<!-- if we have a glancing value, then immediately recurse
without processing if we have a match -->
<if name="@glance@">
<c:case>
<c:when name="@car@">
<c:eq>
<c:value-of name="@glance@" />
</c:eq>
</c:when>
<c:recurse>
<c:arg name="@set@">
<c:value-of name="@cdr@" />
</c:arg>
</c:recurse>
</c:case>
</if>
<!-- otherwise, process as normal -->
<c:otherwise>
<unless name="@merge@">
<!-- here's our recursive operation: cons the result of processing
this car with the result of recursively processing the cdr
(note that c:recurse will recurse on the function that applied
this template, _not_ on the template itself)-->
<c:cons>
<param-copy name="@values@" />
<c:recurse>
<c:arg name="@set@">
<c:value-of name="@cdr@" />
</c:arg>
</c:recurse>
</c:cons>
</unless>
<if name="@merge@">
<!-- the order is different from the cons above to maintain
consistency in the returned set -->
<c:apply name="vmerge">
<c:arg name="vector">
<c:recurse>
<c:arg name="@set@">
<c:value-of name="@cdr@" />
</c:arg>
</c:recurse>
</c:arg>
<c:arg name="onto">
<param-copy name="@values@" />
</c:arg>
</c:apply>
</if>
</c:otherwise>
</c:cases>
</c:let>
</c:otherwise>
</c:cases>
</c:let>
</template>
<!--
Like cons-until-empty, except that it merges each application instead of cons-ing it.
This template recurses and, as such, should only be used within functions.
-->
<template name="_merge-until-empty_" desc="Generate empty base case for functions that recursively merge on cdrs of sets">
<param name="@values@" desc="Body" />
<param name="@set@" desc="Set to operate on" />
<param name="@car@" desc="Variable in which to store car of the set" />
<param name="@cdr@" desc="Variable in which to store the cdr of the set">
<text>__cdr</text>
</param>
<param name="@glance@" desc="Glance at (but do nothing with) this value; recurse without action" />
<!-- to reduce duplicate template code, we simply set a merge flag on cons-until-empty -->
<t:cons-until-empty set="@set@" car="@car@" cdr="@cdr@" glance="@glance@" merge="true">
<param-copy name="@values@" />
</t:cons-until-empty>
</template>
<!--
Merges two vectors
-->
<function name="vmerge" desc="Merge two vectors (does not remove duplicates)">
<param name="vector" type="float" set="vector" desc="Vector to merge" />
<param name="onto" type="float" set="vector" desc="Vector to append to" />
<!-- the template handles much of this for us: just keep cons'ing the car
until we have nothing more to cons, then that gets cons'd onto the
base -->
<t:cons-until-empty set="vector" car="car" base="onto">
<c:value-of name="car" />
</t:cons-until-empty>
</function>
</package>