import std.exception; import sdlang.parser; auto root = parseSource(` foo 1 "a" 2 "b" foo 3 "c" 4 "d" // expectTagValue considers this to override the first foo bar "hi" bar 379 // expectTagValue considers this to override the first bar `); assert( root.expectTagValue!int("foo") == 3 ); assert( root.expectTagValue!string("foo") == "c" ); // The last "bar" tag doesn't have a string (only the first "bar" tag does) // If you'd rather receive a default value than an exception, use `getTagValue` instead. assertThrown!ValueNotFoundException( root.expectTagValue!string("bar") ); // Tag not found assertThrown!TagNotFoundException( root.expectTagValue!int("doesnt-exist") ); // Using namespaces: root = parseSource(` ns1:foo 1 "a" 2 "b" ns1:foo 3 "c" 4 "d" ns2:foo 11 "aa" 22 "bb" ns2:foo 33 "cc" 44 "dd" ns1:bar "hi" ns1:bar 379 // expectTagValue considers this to override the first bar `); assert( root.expectTagValue!int("ns1:foo") == 3 ); assert( root.expectTagValue!int("*:foo" ) == 33 ); // Search all namespaces assert( root.expectTagValue!string("ns1:foo") == "c" ); assert( root.expectTagValue!string("*:foo" ) == "cc" ); // Search all namespaces // The last "bar" tag doesn't have a string (only the first "bar" tag does) assertThrown!ValueNotFoundException( root.expectTagValue!string("*:bar") ); // Namespace not found assertThrown!TagNotFoundException( root.expectTagValue!int("doesnt-exist:bar") );
Lookup a child tag by name, and retrieve a value of type T from it. Throws if not found,
Useful if you only expect one value of type T from a given tag. Only looks for immediate child tags of this, doesn't search recursively.
This is a shortcut for expectTag().expectValue().