JetCore/__eval.cpp

#include "__eval.h"
#include "Exception.h"

namespace jet {

   // <eval> is not a jet-2.0 addition - it's a genuine jet-1.4 tag that was
   // simply never implemented in 2.0 at all (no class, no dispatch entry
   // anywhere). SESSIONCTL.tag's own <page> definition depends on it
   // throughout - capturing a tag's own invocation content into a named
   // variable (<eval name="_BODY"><container></eval>, often with
   // scope="parent" so a nested custom tag can write back into its
   // caller's scope: <eval name="AUTHOR" scope="parent">...), and also
   // using it bare (no name=) to render an <include>'d file's content
   // inline (<eval><include file="...page"></eval>). Without this tag,
   // all of that content was silently falling through as undefined-tag
   // literal text, which is why a real, unmodified SESSIONCTL.tag <page>
   // never produced its actual rendered body.
   //
   // <eval name="X" [scope="local|parent|global"]>content</eval> - same
   // capture semantics as <set name="X">content</set> (Tag::storeVariable
   // already implements exactly this: interpret the container, then store
   // the result - raw if the container itself specified eval="no", already
   // evaluated otherwise - into variable X at the requested scope,
   // defaulting to global like <set> does). Reused directly rather than
   // reimplemented, since it's the identical contract under a different
   // tag name.
   //
   // <eval>content</eval> (no name=) - content is interpreted and flows to
   // normal output, exactly like any ordinary container-having tag; no
   // special-casing needed since output/evaluate already default to true
   // on the base Tag class and the destructor's copyContainer(out,
   // parentOut) handles the rest once processContainer(container) below
   // has populated `out`.
   __eval::__eval(coreutils::ZString &in, coreutils::MString &parentOut, Global &global, Tag *parent, Tag *local) : Tag(in, parentOut, global, parent, local) {
      if(keywordDefined("name")) {
	 storeVariable(resolveKeyword("name"));
	 output = false;
      } else if(hasContainer) {
	 processContainer(container);
      }
   }

}