import ballerina/io;
function foo(json j) returns error? {
match j {
// Match statement can be used to match maps.
// Patterns on the left hand side in a match statement can have variable
// parts that can be captured.
// Match semantics are open (may have fields other than those
// specified in the pattern).
{command: "add", amount: var x} => {
decimal n = check x.ensureType(decimal);
add(n);
}
_ => {
return error("invalid command");
}
}
}
decimal total = 0;
function add(decimal amount) {
total += amount;
io:println("Total: ", total);
}
public function main() returns error? {
check foo({command: "add", amount: 100, status: "pending"});
check foo({command: "add", amount: 10});
check foo({command: "subtract", amount: 100});
}
Match Statement With MapsMatch statement can be used to match maps.
Patterns on the left hand side in a match statement can have variable
parts that can be captured.
Useful for working directly with |
import ballerina/io;
function foo(json j) returns error? {
match j {
{command: "add", amount: var x} => {
decimal n = check x.ensureType(decimal);
add(n);
}
Match statement can be used to match maps. Patterns on the left hand side in a match statement can have variable parts that can be captured. Match semantics are open (may have fields other than those specified in the pattern).
_ => {
return error("invalid command");
}
}
}
decimal total = 0;
function add(decimal amount) {
total += amount;
io:println("Total: ", total);
}
public function main() returns error? {
check foo({command: "add", amount: 100, status: "pending"});
check foo({command: "add", amount: 10});
check foo({command: "subtract", amount: 100});
}
bal run match_statement_with_maps.bal
Total: 100.0
Total: 110.0
error: invalid command {}
