javax0.jamal.yaml.Define Maven / Gradle / Ivy

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yaml module for Jamal
There is a newer version: 2.8.1
package javax0.jamal.yaml;

import javax0.jamal.api.BadSyntax;
import javax0.jamal.api.InnerScopeDependent;
import javax0.jamal.api.Input;
import javax0.jamal.api.Macro;
import javax0.jamal.api.Processor;
import org.yaml.snakeyaml.Yaml;

import static javax0.jamal.api.SpecialCharacters.DEFINE_OPTIONALLY;
import static javax0.jamal.api.SpecialCharacters.ERROR_REDEFINE;
import static javax0.jamal.tools.InputHandler.convertGlobal;
import static javax0.jamal.tools.InputHandler.fetchId;
import static javax0.jamal.tools.InputHandler.firstCharIs;
import static javax0.jamal.tools.InputHandler.skip;
import static javax0.jamal.tools.InputHandler.skipWhiteSpaces;
import static javax0.jamal.tools.InputHandler.skipWhiteSpaces2EOL;

public class Define implements Macro, InnerScopeDependent {
    final Yaml yaml = YamlFactory.newYaml();

    @Override
    public String evaluate(Input in, Processor processor) throws BadSyntax {
        final String id = getMacroIdentifier(in, processor);
        if (id == null) return "";
        final Object yamlStructure;
        try {
            yamlStructure = yaml.load(in.toString());
        } catch (Exception e) {
            throw new BadSyntax("Cannot load YAML data.", e);
        }
        final var yamlObject = new YamlObject(processor, id, yamlStructure);
        processor.define(yamlObject);
        processor.getRegister().export(yamlObject.getId());
        return "";
    }

    static String getMacroIdentifier(Input in, Processor processor) throws BadSyntax {
        skipWhiteSpaces(in);
        var optional = firstCharIs(in, DEFINE_OPTIONALLY);
        var noRedefine = firstCharIs(in, ERROR_REDEFINE);
        if (optional || noRedefine) {
            skip(in, 1);
            skipWhiteSpaces(in);
        }

        final var id = fetchId(in);
        if (processor.isDefined(convertGlobal(id))) {
            if (optional) {
                return null;
            }
            BadSyntax.when(noRedefine,  "The macro '%s' was already defined.", id);
        }
        skipWhiteSpaces(in);
        BadSyntax.when(!firstCharIs(in, '='),  "yaml '%s' has no '=' to body", id);
        skip(in, 1);
        skipWhiteSpaces2EOL(in);
        return id;
    }

    @Override
    public String getId() {
        return "yaml:define";
    }
}