Examples with BLangMatch org.wso2.ballerinalang.compiler.tree.statements.BLangMatch used on opensource projects

Example 6 with BLangMatch

use of org.wso2.ballerinalang.compiler.tree.statements.BLangMatch in project ballerina by ballerina-lang.

the class Desugar method visit.

@Override
public void visit(BLangAssignment assignNode) {
    if (assignNode.expr.type.tag == TypeTags.STREAM && assignNode.varRefs.get(0) instanceof BLangSimpleVarRef) {
        ((BLangRecordLiteral) assignNode.expr).name = ((BLangSimpleVarRef) assignNode.varRefs.get(0)).variableName;
    }
    assignNode.varRefs = rewriteExprs(assignNode.varRefs);
    assignNode.expr = rewriteExpr(assignNode.expr);
    result = assignNode;
    if (!assignNode.safeAssignment) {
        return;
    }
    // Desugar the =? operator with the match statement
    // 
    // e.g.
    // File f;
    // .....
    // f =? openFile("/tmp/foo.txt"); // openFile: () -> (File | error)
    // 
    // {
    // match openFile("/tmp/foo.txt") {
    // File _$_f1 => f = _$_f1;
    // error e => throw e | return e
    // }
    // }
    BLangBlockStmt safeAssignmentBlock = ASTBuilderUtil.createBlockStmt(assignNode.pos, new ArrayList<>());
    BLangExpression lhsExpr = assignNode.varRefs.get(0);
    BLangMatchStmtPatternClause patternSuccessCase;
    if (assignNode.declaredWithVar) {
        BVarSymbol varSymbol = ((BLangSimpleVarRef) lhsExpr).symbol;
        BLangVariable variable = ASTBuilderUtil.createVariable(assignNode.pos, "", lhsExpr.type, null, varSymbol);
        BLangVariableDef variableDef = ASTBuilderUtil.createVariableDef(assignNode.pos, variable);
        safeAssignmentBlock.stmts.add(variableDef);
        patternSuccessCase = getSafeAssignSuccessPattern(assignNode.pos, lhsExpr.type, true, varSymbol, null);
    } else {
        patternSuccessCase = getSafeAssignSuccessPattern(assignNode.pos, lhsExpr.type, false, null, lhsExpr);
    }
    // Create the pattern to match the success case
    BLangMatchStmtPatternClause patternErrorCase = getSafeAssignErrorPattern(assignNode.pos, this.env.enclInvokable.symbol);
    // Create the match statement
    BLangMatch matchStmt = ASTBuilderUtil.createMatchStatement(assignNode.pos, assignNode.expr, new ArrayList<BLangMatchStmtPatternClause>() {

        {
            add(patternSuccessCase);
            add(patternErrorCase);
        }
    });
    // var f =? foo() -> var f;
    assignNode.expr = null;
    assignNode.safeAssignment = false;
    safeAssignmentBlock.stmts.add(matchStmt);
    result = rewrite(safeAssignmentBlock, this.env);
}

Example 7 with BLangMatch

use of org.wso2.ballerinalang.compiler.tree.statements.BLangMatch in project ballerina by ballerina-lang.

the class SemanticAnalyzer method visit.

public void visit(BLangMatch matchNode) {
    List<BType> exprTypes = typeChecker.checkExpr(matchNode.expr, env, Lists.of(symTable.noType));
    if (exprTypes.size() > 1) {
        dlog.error(matchNode.expr.pos, DiagnosticCode.MULTI_VAL_EXPR_IN_SINGLE_VAL_CONTEXT);
        return;
    } else if (exprTypes.size() == 0) {
        dlog.error(matchNode.expr.pos, DiagnosticCode.INVALID_EXPR_IN_MATCH_STMT);
        return;
    } else if (exprTypes.get(0).tag == TypeTags.UNION) {
        BUnionType unionType = (BUnionType) exprTypes.get(0);
        exprTypes = new ArrayList<>(unionType.memberTypes);
    }
    // visit patterns
    matchNode.patternClauses.forEach(patternClause -> patternClause.accept(this));
    matchNode.exprTypes = exprTypes;
}

Example 8 with BLangMatch

use of org.wso2.ballerinalang.compiler.tree.statements.BLangMatch in project ballerina by ballerina-lang.

the class Desugar method visit.

@Override
public void visit(BLangVariableDef varDefNode) {
    if (varDefNode.var.expr instanceof BLangRecordLiteral && ((BLangRecordLiteral) varDefNode.var.expr).type.tag == TypeTags.STREAM) {
        ((BLangRecordLiteral) varDefNode.var.expr).name = varDefNode.var.name;
    }
    varDefNode.var = rewrite(varDefNode.var, env);
    BLangVariable varNode = varDefNode.var;
    // Generate default init expression, if rhs expr is null
    if (varNode.expr == null) {
        varNode.expr = getInitExpr(varNode.type);
    }
    if (!varNode.safeAssignment) {
        result = varDefNode;
        return;
    }
    // Desugar the =? operator with the match statement
    // 
    // e.g.
    // var f =? openFile("/tmp/foo.txt"); // openFile: () -> (File | error)
    // 
    // {
    // File f;
    // match openFile("/tmp/foo.txt") {
    // File _$_f1 => f = _$_f1;
    // error e => throw e | return e
    // }
    // }
    // Create the pattern to match the success case
    BLangMatchStmtPatternClause patternSuccessCase = getSafeAssignSuccessPattern(varNode.pos, varNode.symbol.type, true, varNode.symbol, null);
    BLangMatchStmtPatternClause patternErrorCase = getSafeAssignErrorPattern(varNode.pos, varNode.symbol.owner);
    // Create the match statement
    BLangMatch matchStmt = ASTBuilderUtil.createMatchStatement(varNode.expr.pos, varNode.expr, new ArrayList<BLangMatchStmtPatternClause>() {

        {
            add(patternSuccessCase);
            add(patternErrorCase);
        }
    });
    // var f =? foo() -> var f;
    varNode.expr = null;
    varNode.safeAssignment = false;
    BLangBlockStmt safeAssignmentBlock = ASTBuilderUtil.createBlockStmt(varDefNode.pos, new ArrayList<BLangStatement>() {

        {
            add(varDefNode);
            add(matchStmt);
        }
    });
    result = rewrite(safeAssignmentBlock, this.env);
}

Example 9 with BLangMatch

use of org.wso2.ballerinalang.compiler.tree.statements.BLangMatch in project ballerina by ballerina-lang.

the class Desugar method visit.

@Override
public void visit(BLangMatch matchStmt) {
    // Here we generate an if-else statement for the match statement
    // Here is an example match statement
    // 
    // match expr {
    // int k => io:println("int value: " + k);
    // string s => io:println("string value: " + s);
    // json j => io:println("json value: " + s);
    // 
    // }
    // 
    // Here is how we convert the match statement to an if-else statement. The last clause should always be the
    // else clause
    // 
    // string | int | json | any _$$_matchexpr = expr;
    // if ( _$$_matchexpr isassignable int ){
    // int k = (int) _$$_matchexpr; // unbox
    // io:println("int value: " + k);
    // 
    // } else if (_$$_matchexpr isassignable string ) {
    // string s = (string) _$$_matchexpr; // unbox
    // io:println("string value: " + s);
    // 
    // } else if ( _$$_matchexpr isassignable float ||    // should we consider json[] as well
    // _$$_matchexpr isassignable boolean ||
    // _$$_matchexpr isassignable json) {
    // 
    // } else {
    // // handle the last pattern
    // any case..
    // }
    // 
    // First create a block statement to hold generated statements
    BLangBlockStmt matchBlockStmt = (BLangBlockStmt) TreeBuilder.createBlockNode();
    matchBlockStmt.pos = matchStmt.pos;
    // Create a variable definition to store the value of the match expression
    String matchExprVarName = GEN_VAR_PREFIX.value;
    BLangVariable matchExprVar = ASTBuilderUtil.createVariable(matchStmt.expr.pos, matchExprVarName, matchStmt.expr.type, matchStmt.expr, new BVarSymbol(0, names.fromString(matchExprVarName), this.env.scope.owner.pkgID, matchStmt.expr.type, this.env.scope.owner));
    // Now create a variable definition node
    BLangVariableDef matchExprVarDef = ASTBuilderUtil.createVariableDef(matchBlockStmt.pos, matchExprVar);
    // Add the var def statement to the block statement
    // string | int _$$_matchexpr = expr;
    matchBlockStmt.stmts.add(matchExprVarDef);
    // Create if/else blocks with typeof binary expressions for each pattern
    matchBlockStmt.stmts.add(generateIfElseStmt(matchStmt, matchExprVar));
    rewrite(matchBlockStmt, this.env);
    result = matchBlockStmt;
}

Example 10 with BLangMatch

use of org.wso2.ballerinalang.compiler.tree.statements.BLangMatch in project ballerina by ballerina-lang.

the class BLangPackageBuilder method completeMatchNode.

public void completeMatchNode(DiagnosticPos pos, Set<Whitespace> ws) {
    BLangMatch matchStmt = this.matchStmtStack.removeFirst();
    matchStmt.pos = pos;
    matchStmt.addWS(ws);
    matchStmt.expr = (BLangExpression) this.exprNodeStack.pop();
    addStmtToCurrentBlock(matchStmt);
}