Tree Editor Commands

Programs are trees, not strings.

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Code should be edited using a “tree editor” that respects the syntactic structure of programs, rather than a “text editor” that doesn’t. This is made difficult by the fact that there is a huge amount of infrastructure already in place around text files. Nevertheless, we’ll get there eventually.

Here are some quick thoughts on a grouping of tree editing commands. The cursor will either be around a node in the tree, in which case it refers to the node and all of its children, or it will be ‘editing’ a particular node, in which case you’re manipulating the contents of just that node itself. The “Navigation” directions are relative to the code tree: “up” means “your parent”, and right means “your next sibling”.

Navigation

• up (up arrow, ‘k’)
• down (down arrow, ‘j’)
• left (left arrow, ‘h’)
• right (right arrow, ‘l’)
• (Add ‘shift’ to go all the way up, right, etc.)

Commands

• insert node (‘i’, followed by a Nav direction)
• delete node (‘d’, followed by a Nav direction)
• swap nodes (‘s’, followed by a Nav direction)
• cut, copy, paste node; undo, redo; find (standard)

Editing

• edit node contents (‘enter’)
• done editing node contents (‘enter’)
• done editing node contents, and go right (‘tab’)

Kenny & John’s Tree Editor

Here are the commands from a tree editor project at Brown. They are vim-like, and have two modes: normal mode and insert mode.

Navigation

• up (up arrow, ‘i’)
• down (down arrow, ‘k’)
• left sibling (left arrow, ‘j’)
• right sibling (right arrow, ‘l’)
• left inorder (‘u’)
• right inorder (‘o’)

Commands

• insert group (‘tab’ = ‘nk’)
• exit group (‘space’ = ‘if’)
• wrap (‘w’)
• unwrap (‘e’)
• swap (‘s’)
• delete (‘d’)
• select all (‘a’)
• select none (‘f’)
• reverse selection (‘r’)
• goto first (‘g’)
• cut, copy, paste node; undo, redo (standard)
• find (none yet)

Editing

• normal mode (‘enter’)
• insert mode (‘h’)