Editing Expression

Using XForms

Balisage 2012

Montréal, 7 August 2012

http://www.blackmesatech.com/2012/08/demos/jam.html

Suppose ...

specialized recursive formula language (math, logic, ...)
Web interface
XML processing
Web interface + XML processing = XForms
... so we need an XML form for formulas

A sample formula

For example:

((p ∨ (q ∧ r)) ⊃ ((p ∨ q) ∧ (p ∨ r)))

An XML form

We might represent this as:

  <implies>
    <or>
      <var id="p"/>
      <and>
        <var id="q"/>
        <var id="r"/>
      </and>
    </or>
    <and>
      <or>
        <var id="p"/>
        <var id="q"/>
      </or>
      <or>
        <var id="p"/>
        <var id="r"/>
      </or>
    </and>
  </implies>

Or ...

Or as:

  <implies rms="((p ∨ (q ∧ r)) ⊃ ((p ∨ q) ∧ (p ∨ r)))">
    <or rms="(p ∨ (q ∧ r))">
      <var id="p" rms="p"/>
      <and rms="(q ∧ r)">
        <var id="q" rms="q"/>
        <var id="r" rms="r"/>
      </and>
    </or>
    <and rms="((p ∨ q) ∧ (p ∨ r))">
      <or rms="(p ∨ q)">
        <var id="p" rms="p"/>
        <var id="q" rms="q"/>
      </or>
      <or rms="(p ∨ r)">
        <var id="p" rms="p"/>
        <var id="r" rms="r"/>
      </or>
    </and>
  </implies>

How do we get formulas into XML?

conventional XML editor (Emacs, Oxygen ...)
ASCII format + parser
- Literal? ((p ∨ (q ∧ r)) ⊃ ((p ∨ q) ∧ (p ∨ r)))
- Typeable? ((p or (q and r)) implies ((p or q) and (p or r)))
- Lispy? (implies (or p (and q r)) (and (or p q) (or p r)))
... or XForms (demo)

Samples

((p ⊃ (q ⊃ r)) ⊃ ((p ⊃ q) ⊃ (p ⊃ r)))
(q ⊃ (q ⊃ p))
(((p ⊃ q) ∧ (q ⊃ r)) ⊃ (p ⊃ r))
(((p ⊃ q) ∧ (p ⊃ r)) ⊃ (p ⊃ (q ∧ r)))
((((p ⊃ r) ∧ (q ⊃ r)) ∧ (p ∨ q)) ⊃ r)
(⁓(p ∧ q) ⊃ (⁓p ∨ ⁓q))
(⁓(p ∨ q) ⊃ (⁓p ∧ ⁓q))