Define.java

package fitnesse.wikitext.parser;

import fitnesse.html.HtmlTag;

public class Define extends SymbolType implements Rule, Translation {
    public Define() {
        super("Define");
        wikiMatcher(new Matcher().startLineOrCell().string("!define"));
        wikiRule(this);
        htmlTranslation(this);
    }

    @Override
    public Maybe<Symbol> parse(Symbol current, Parser parser) {
        if (!parser.isMoveNext(SymbolType.Whitespace)) return Symbol.nothing;

        Maybe<String> name = parser.parseToAsString(SymbolType.Whitespace);
        if (name.isNothing()) return Symbol.nothing;
        String variableName = name.getValue();
        if (!ScanString.isVariableName(variableName)) return Symbol.nothing;

        Symbol next = parser.moveNext(1);
        Maybe<String> valueString = (next.isType(SymbolType.Text))
                ? copyVariableValue(parser, next)
                : parseVariableValue(parser, next);
        if (valueString.isNothing()) return Symbol.nothing;

        String variableValue = valueString.getValue();
        parser.getPage().putVariable(variableName, variableValue);
        return new Maybe<>(current.add(variableName).add(variableValue));
    }

    private Maybe<String> copyVariableValue(Parser parser, Symbol next) {
      String fromVariableName = next.getContent();
      if (!ScanString.isVariableName(fromVariableName)) return Maybe.noString;
      return parser.getVariableSource().findVariable(fromVariableName);
    }

    private Maybe<String> parseVariableValue(Parser parser, Symbol next) {
      SymbolType close = next.getType().closeType();
      if (close == SymbolType.Empty) return Maybe.noString;
      return parser.parseToAsString(close);
    }

    @Override
    public String toTarget(Translator translator, Symbol symbol) {
        HtmlTag result = new HtmlTag("span", "variable defined: "
                + translator.translate(symbol.childAt(0))
                + "="
                + translator.translate(symbol.childAt(1)));
        result.addAttribute("class", "meta");
        return result.html();
    }

}