Naming and program structure

5. Naming and program structure (since v0.0)

A program is paper square followed by statements, executed top to bottom. A name must be defined before it is used.

• Crease statement — binds a crease, or is anonymous; with @ it also folds (§4.6):

  --d1: through .a .c              ; named precrease
  map .a onto .c                   ; anonymous precrease
  @map .a onto .c moving .a        ; fold (valley)

• Point statement — binds a derived point:

  .center: cross --d1 --d2

• Flip statement (since v0.7-dev) — turns the sheet over (§4.7):

  flip

Derived points and named creases are usable in any later statement. ; begins a line comment.

Concrete syntax (keywords, sigils) is stable as of v0.0 but may still be revised before v1.0.