Method zip_map

output/java/1.4.19/Interpreter.java:877–941

(InstanceScope scope, List<Object> exprs, ST prototype)

    // todo: i, i0 not set unless mentioned? map:{k,v | ..}?

    protected ST.AttributeList zip_map(InstanceScope scope, List<Object> exprs, ST prototype) {
        if ( exprs==null || prototype==null || exprs.size()==0) {
            return null; // do not apply if missing templates or empty values
        }
        // make everything iterable
        for (int i = 0; i <exprs.size(); i++) {
            Object attr = exprs.get(i);
            if ( attr !=null ) exprs.set(i, convertAnythingToIterator(scope, attr));
        }

        // ensure arguments line up

        int numExprs = exprs.size();
        CompiledST code = prototype.impl;
        Map<String, FormalArgument> formalArguments = code.formalArguments;
        if ( !code.hasFormalArgs|| formalArguments==null ) {
            errMgr.runTimeError(this, scope, ErrorType.MISSING_FORMAL_ARGUMENTS);
            return null;
        }

        // todo: track formal args not names for efficient filling of locals
        String[] formalArgumentNames = formalArguments.keySet().toArray(new String[formalArguments.size()]);
        int nformalArgs = formalArgumentNames.length;
        if ( prototype.isAnonSubtemplate() ) nformalArgs -= predefinedAnonSubtemplateAttributes.size();
        if ( nformalArgs != numExprs ) {
            errMgr.runTimeError(this,
                                scope,
                                ErrorType.MAP_ARGUMENT_COUNT_MISMATCH,
                                numExprs,
                                nformalArgs);
            // TODO just fill first n
            // truncate arg list to match smaller size
            int shorterSize = Math.min(formalArgumentNames.length, numExprs);
            numExprs = shorterSize;
            String[] newFormalArgumentNames = new String[shorterSize];
            System.arraycopy(formalArgumentNames, 0, newFormalArgumentNames, 0, shorterSize);
            formalArgumentNames = newFormalArgumentNames;
        }

        // keep walking while at least one attribute has values
        ST.AttributeList results = new ST.AttributeList();
        int i = 0; // iteration number from 0
        while ( true ) {
            // get a value for each attribute in list; put into ST instance
            int numEmpty = 0;
            ST embedded = group.createStringTemplateInternally(prototype);
            embedded.rawSetAttribute("i0", i);
            embedded.rawSetAttribute("i", i+1);
            for (int a = 0; a < numExprs; a++) {
                Iterator<?> it = (Iterator<?>)exprs.get(a);
                if ( it !=null && it.hasNext() ) {
                    String argName = formalArgumentNames[a];
                    Object iteratedValue = it.next();
                    embedded.rawSetAttribute(argName, iteratedValue);
                }
                else {
                    numEmpty++;
                }