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digitalmars.D - Discussion Thread: DIP 1030--Named Arguments--Final Review

https://forum.dlang.org/post/osiiuzwesgmaegekodif forum.dlang.org

On Monday, 11 May 2020 at 11:37:07 UTC, Mike Parker wrote:
 This is the discussion thread for the Final Review of DIP 1030, 
 "Named Arguments":

 https://github.com/dlang/DIPs/blob/7d114c93edb02d8fc4b05f0716bdb6057905fec2/DIPs/DIP1030.md
I dream it will be like this. 1. Of course, named args delimiter is ':'. Same in struct initialization: Border b = { width: 1 }; struct Border { int width; }; 2. Named args in Class constructor: // usage auto inp = new Input( border: 1 ); // class class Input { Border border; this() {} // human-coded ctor // auto generated from "new Row( border: 1 )" // if not found human-coded ctor with same args this( Border border ) { this.border = border; this(); // call human-coded ctor } } 3. Named args in Class constructor merged with ctor args: // usage auto inp = new Input( "Label text", border: 1 ); // class class Input { Border border; string label_text; // human-coded ctor this( string label_text ) { this.label_text = label_text; } // auto generated from "new Row( "Label text", border: 1 )" // if not found human-coded ctor with same args this( string label_text, Border border ) { this.border = border; this( label_text ); // call human coded ctor } } 4. Of course, all inline: // usage auto inp = new Input( border: 1, "Label text" ); // class class Input { Border border; string label_text; // human coded ctor this( string label_text ) { this.label_text = label_text; } // auto generated from "new Row( border: 1, "Label text" )" this( Border border, string label_text ) { // from named args this.border = border; // inlined from human coded ctor this.label_text = label_text; } } 5. Class fields is named arguments for ctor. // for class: class Input { Border border; string label_text; } // possible calls auto a1 = Input( border: 1 ); auto a2 = Input( label_text: "Score" ); auto a3 = Input( border: 1, label_text: "Score" ); auto a4 = Input( label_text: "Score", border: 1 ); 6. Function named args: // usage borderedInput( border: 1 ); // function auto borderedInput( Border border ) { return new Input( border: border ); } And then we will write clean code for UI, like in Dart/Flutter: auto inp = new Input( "Label text", border : 1, child : new Image( src: "info.png" ) );
Jul 03