Windrose

Alphabet

Terminals are steps from the origin: ↑ north, → east, ← west, ↓ south. The trace is the left-to-right terminal prefix of the sentential form (drawing stops at the first remaining nonterminal).

Grammar

Add nonterminals as cards. Each row is one production. Empty row is ε. Click a symbol or + to open the palette. Click a start chip to choose the start symbol.

Trace

Click a nonterminal chip in the sentential form and pick a branch. Random samples a complete word. The terminal p metronome biases Random toward growing (left) or halting (right). Undo / Reset walk the derivation back.

Keyboard (always)

• Tab move between controls
• Enter / Space activate
• ← → move along a row of symbols
• Esc close palette, picker, or help

Vim

Turn on Vim in the header. There is no key that enables it. Bindings below work only while it is on.

Panes

• gh grammar
• gl trace
• Tab cycle panes
• g1–g9 load a preset
• ? this help
• Esc back to NORMAL

Grammar

• h j k l move
• gg / G first / last nonterminal
• w / b next / previous card
• i rename
• gs set start
• o / O production below / above
• a / I append / insert symbol
• r replace symbol
• x delete symbol
• dd delete production
• dc delete nonterminal
• n new nonterminal

Palette

• hjkl move
• n e w s terminals
• 0 / _ ε
• 1–9 nonterminal
• + new nonterminal
• x remove

Trace

• h l chips
• w / b next / previous nonterminal
• 0 / $ first / last
• Enter / o expand
• r random
• u undo
• R reset
• . repeat last production
• 1–9 pick a branch (in PICK)