Cut-and-Paste

Both textual and structural cut-and-paste are supported.

Textual cut-and-paste is just like the cut and paste of a normal text editor. Arbitrary substrings of text can be cut out and inserted. The commands are cut-text (menu: Edit/Cut Text   X: Ctrl+W;  NT: Ctrl+X), and paste-text (menu: Edit/Paste Text   X: Ctrl+Y   NT: Ctrl+V).

Drag the mouse over a few of the digits in D := 123_456_789; and cut them out using cut-text. Then strike RETURN.

Reposition the insertion cursor somewhere within the remaining digits in the constant and paste the digits back in using paste-text. Then strike RETURN.

Notice that the underscores are automatically adjusted for you.

Structural cut-and-paste operates similarly, but with structural fragments of the object. A structural cut clips the structural selection into a special clipboard buffer named *clipped*, and replaces the structural selection with the appropriate placeholder. The commands are cut-structure (menu: Edit/Cut Structure   X: Ctrl+Shift+W   NT: Ctrl+Shift+X), and paste-structure (menu: Edit/Paste Structure   X: Ctrl+Shift+Y   NT: Ctrl+Shift+V).

Position the structural selection at the 100. Then remove it using cut-structure.

A structural paste is valid only when the structural selection is a placeholder of the same syntactic category as the contents of the clipboard. For example, an expression can never be pasted on top of an existing expression, or into a position where a statement is expected. This guarantees that the object being edited remains well formed.

Position the structural selection at the <identifier> placeholder. Attempt to insert the 100 using paste-structure.

Now select X or Y and again attempt to insert the 100 using paste-structure.

Finally, select the <expression> placeholder and insert the 100 using paste-structure.

Note that an error message is printed in the status pane when an incorrect structural paste is attempted.