Examples with FunctionDetails org.hl7.fhir.r4.utils.FHIRPathEngine.IEvaluationContext.FunctionDetails used on opensource projects

Example 6 with FunctionDetails

use of org.hl7.fhir.r4.utils.FHIRPathEngine.IEvaluationContext.FunctionDetails in project org.hl7.fhir.core by hapifhir.

the class FHIRPathEngine method parseExpression.

private ExpressionNode parseExpression(FHIRLexer lexer, boolean proximal) throws FHIRLexerException {
    ExpressionNode result = new ExpressionNode(lexer.nextId());
    SourceLocation c = lexer.getCurrentStartLocation();
    result.setStart(lexer.getCurrentLocation());
    // special:
    if (lexer.getCurrent().equals("-")) {
        lexer.take();
        lexer.setCurrent("-" + lexer.getCurrent());
    }
    if (lexer.getCurrent().equals("+")) {
        lexer.take();
        lexer.setCurrent("+" + lexer.getCurrent());
    }
    if (lexer.isConstant(false)) {
        checkConstant(lexer.getCurrent(), lexer);
        result.setConstant(lexer.take());
        result.setKind(Kind.Constant);
        result.setEnd(lexer.getCurrentLocation());
    } else if ("(".equals(lexer.getCurrent())) {
        lexer.next();
        result.setKind(Kind.Group);
        result.setGroup(parseExpression(lexer, true));
        if (!")".equals(lexer.getCurrent()))
            throw lexer.error("Found " + lexer.getCurrent() + " expecting a \")\"");
        result.setEnd(lexer.getCurrentLocation());
        lexer.next();
    } else {
        if (!lexer.isToken() && !lexer.getCurrent().startsWith("\""))
            throw lexer.error("Found " + lexer.getCurrent() + " expecting a token name");
        if (lexer.getCurrent().startsWith("\""))
            result.setName(lexer.readConstant("Path Name"));
        else
            result.setName(lexer.take());
        result.setEnd(lexer.getCurrentLocation());
        if (!result.checkName())
            throw lexer.error("Found " + result.getName() + " expecting a valid token name");
        if ("(".equals(lexer.getCurrent())) {
            Function f = Function.fromCode(result.getName());
            FunctionDetails details = null;
            if (f == null) {
                if (hostServices != null)
                    details = hostServices.resolveFunction(result.getName());
                if (details == null)
                    throw lexer.error("The name " + result.getName() + " is not a valid function name");
                f = Function.Custom;
            }
            result.setKind(Kind.Function);
            result.setFunction(f);
            lexer.next();
            while (!")".equals(lexer.getCurrent())) {
                result.getParameters().add(parseExpression(lexer, true));
                if (",".equals(lexer.getCurrent()))
                    lexer.next();
                else if (!")".equals(lexer.getCurrent()))
                    throw lexer.error("The token " + lexer.getCurrent() + " is not expected here - either a \",\" or a \")\" expected");
            }
            result.setEnd(lexer.getCurrentLocation());
            lexer.next();
            checkParameters(lexer, c, result, details);
        } else
            result.setKind(Kind.Name);
    }
    ExpressionNode focus = result;
    if ("[".equals(lexer.getCurrent())) {
        lexer.next();
        ExpressionNode item = new ExpressionNode(lexer.nextId());
        item.setKind(Kind.Function);
        item.setFunction(ExpressionNode.Function.Item);
        item.getParameters().add(parseExpression(lexer, true));
        if (!lexer.getCurrent().equals("]"))
            throw lexer.error("The token " + lexer.getCurrent() + " is not expected here - a \"]\" expected");
        lexer.next();
        result.setInner(item);
        focus = item;
    }
    if (".".equals(lexer.getCurrent())) {
        lexer.next();
        focus.setInner(parseExpression(lexer, false));
    }
    result.setProximal(proximal);
    if (proximal) {
        while (lexer.isOp()) {
            focus.setOperation(ExpressionNode.Operation.fromCode(lexer.getCurrent()));
            focus.setOpStart(lexer.getCurrentStartLocation());
            focus.setOpEnd(lexer.getCurrentLocation());
            lexer.next();
            focus.setOpNext(parseExpression(lexer, false));
            focus = focus.getOpNext();
        }
        result = organisePrecedence(lexer, result);
    }
    return result;
}