import std.exception; import gfx.decl.sdlang.parser; auto root = parseSource(` foo X=1 X="a" X=2 X="b" foo X=3 X="c" X=4 X="d" // getTagAttribute considers this to override the first foo bar X="hi" bar X=379 // getTagAttribute considers this to override the first bar `); assert( root.getTagAttribute!int("foo", "X") == 3 ); assert( root.getTagAttribute!string("foo", "X") == "c" ); // Value found, default value ignored. assert( root.getTagAttribute!int("foo", "X", 999) == 3 ); // Tag not found // If you'd prefer an exception, use `expectTagAttribute` instead of `getTagAttribute` assert( root.getTagAttribute!int("doesnt-exist", "X", 999) == 999 ); assert( root.getTagAttribute!int("doesnt-exist", "X") == 0 ); assert( root.getTagAttribute!int("foo", "doesnt-exist", 999) == 999 ); assert( root.getTagAttribute!int("foo", "doesnt-exist") == 0 ); // The last "bar" tag doesn't have a string (only the first "bar" tag does) assert( root.getTagAttribute!string("bar", "X", "Default") == "Default" ); assert( root.getTagAttribute!string("bar", "X") is null ); // Using namespaces: root = parseSource(` ns1:foo X=1 X="a" X=2 X="b" ns1:foo X=3 X="c" X=4 X="d" ns2:foo X=11 X="aa" X=22 X="bb" ns2:foo X=33 X="cc" X=44 X="dd" ns1:bar attrNS:X="hi" ns1:bar attrNS:X=379 // getTagAttribute considers this to override the first bar `); assert( root.getTagAttribute!int("ns1:foo", "X") == 3 ); assert( root.getTagAttribute!int("*:foo", "X") == 33 ); // Search all namespaces assert( root.getTagAttribute!string("ns1:foo", "X") == "c" ); assert( root.getTagAttribute!string("*:foo", "X") == "cc" ); // Search all namespaces // bar's attribute X is't in the default namespace assert( root.getTagAttribute!int("*:bar", "X", 999) == 999 ); assert( root.getTagAttribute!int("*:bar", "X") == 0 ); // The last "bar" tag's "attrNS:X" attribute doesn't have a string (only the first "bar" tag does) assert( root.getTagAttribute!string("*:bar", "attrNS:X", "Default") == "Default" ); assert( root.getTagAttribute!string("*:bar", "attrNS:X") is null);
Lookup a child tag and attribute by name, and retrieve a value of type T from it. Returns a default value if not found.
Useful if you only expect one attribute of type T from given the tag and attribute names. Only looks for immediate child tags of this, doesn't search recursively.
This is a shortcut for getTag().getAttribute(), except if the tag isn't found, then instead of a null reference error, it will return the requested defaultValue (or T.init by default).