Examples with FHIRLexer org.hl7.fhir.r4b.utils.FHIRLexer used on opensource projects

Example 1 with FHIRLexer

use of org.hl7.fhir.r4b.utils.FHIRLexer in project org.hl7.fhir.core by hapifhir.

the class FHIRPathEngine method parse.

// --- public API -------------------------------------------------------
/**
 * Parse a path for later use using execute
 *
 * @param path
 * @return
 * @throws PathEngineException
 * @throws Exception
 */
public ExpressionNode parse(String path) throws FHIRLexerException {
    FHIRLexer lexer = new FHIRLexer(path);
    if (lexer.done())
        throw lexer.error("Path cannot be empty");
    ExpressionNode result = parseExpression(lexer, true);
    if (!lexer.done())
        throw lexer.error("Premature ExpressionNode termination at unexpected token \"" + lexer.getCurrent() + "\"");
    result.check();
    return result;
}

Example 2 with FHIRLexer

use of org.hl7.fhir.r4b.utils.FHIRLexer in project org.hl7.fhir.core by hapifhir.

the class FHIRPathEngine method gatherPrecedence.

private ExpressionNode gatherPrecedence(FHIRLexer lexer, ExpressionNode start, EnumSet<Operation> ops) {
    assert (start.isProximal());
    // is there anything to do?
    boolean work = false;
    ExpressionNode focus = start.getOpNext();
    if (ops.contains(start.getOperation())) {
        while (focus != null && focus.getOperation() != null) {
            work = work || !ops.contains(focus.getOperation());
            focus = focus.getOpNext();
        }
    } else {
        while (focus != null && focus.getOperation() != null) {
            work = work || ops.contains(focus.getOperation());
            focus = focus.getOpNext();
        }
    }
    if (!work)
        return start;
    // entry point: tricky
    ExpressionNode group;
    if (ops.contains(start.getOperation())) {
        group = newGroup(lexer, start);
        group.setProximal(true);
        focus = start;
        start = group;
    } else {
        ExpressionNode node = start;
        focus = node.getOpNext();
        while (!ops.contains(focus.getOperation())) {
            node = focus;
            focus = focus.getOpNext();
        }
        group = newGroup(lexer, focus);
        node.setOpNext(group);
    }
    // focus points at the group.group
    do {
        // run until we find the end of the sequence
        while (ops.contains(focus.getOperation())) focus = focus.getOpNext();
        if (focus.getOperation() != null) {
            group.setOperation(focus.getOperation());
            group.setOpNext(focus.getOpNext());
            focus.setOperation(null);
            focus.setOpNext(null);
            // now look for another sequence, and start it
            ExpressionNode node = group;
            focus = group.getOpNext();
            if (focus != null) {
                while (focus == null && !ops.contains(focus.getOperation())) {
                    node = focus;
                    focus = focus.getOpNext();
                }
                if (focus != null) {
                    // && (focus.Operation in Ops) - must be true
                    group = newGroup(lexer, focus);
                    node.setOpNext(group);
                }
            }
        }
    } while (focus != null && focus.getOperation() != null);
    return start;
}

Example 3 with FHIRLexer

use of org.hl7.fhir.r4b.utils.FHIRLexer in project org.hl7.fhir.core by hapifhir.

the class FHIRPathEngine method newGroup.

private ExpressionNode newGroup(FHIRLexer lexer, ExpressionNode next) {
    ExpressionNode result = new ExpressionNode(lexer.nextId());
    result.setKind(Kind.Group);
    result.setGroup(next);
    result.getGroup().setProximal(true);
    return result;
}

Example 4 with FHIRLexer

use of org.hl7.fhir.r4b.utils.FHIRLexer 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) {
                details = hostServices != null ? hostServices.resolveFunction(result.getName()) : null;
                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;
}

Example 5 with FHIRLexer

use of org.hl7.fhir.r4b.utils.FHIRLexer in project org.hl7.fhir.core by hapifhir.

the class FHIRPathEngine method parse.

/**
 * Parse a path that is part of some other syntax
 *
 * @return
 * @throws PathEngineException
 * @throws Exception
 */
public ExpressionNode parse(FHIRLexer lexer) throws FHIRLexerException {
    ExpressionNode result = parseExpression(lexer, true);
    result.check();
    return result;
}