PIDE is a framework for sophisticated Prover IDEs, based on Isabelle/Scala technology that is integrated with Isabelle. It is built around a concept of asynchronous document processing, which is supported natively by the parallel proof engine implemented in Isabelle/ML.

Isabelle/jEdit is the flagship application of the PIDE framework — it is ready for small and large Isabelle applications, for beginners and experts alike.

Research and implementation of concepts around PIDE has started around 2008 and was kindly supported by BMBF (http://www.bmbf.de), Université Paris-Sud (http://www.u-psud.fr), Digiteo (http://www.digiteo.fr), and ANR (http://www.agence-nationale-recherche.fr).

The Isabelle/jEdit Prover IDE

Isabelle/jEdit consists of some plugins for the well-known jEdit text editor framework (http://www.jedit.org), according to the following principles.

• The original jEdit look-and-feel is generally preserved, although some default properties have been changed to accommodate Isabelle (e.g. the text area font).
• Formal Isabelle/Isar text is checked asynchronously while editing. The user is in full command of the editor, and the prover refrains from locking portions of the buffer.
• Prover feedback works via colors, boxes, squiggly underline, hyperlinks, popup windows, icons, clickable output, all based on semantic markup produced by Isabelle in the background.
• Using the mouse together with the modifier key CONTROL (Linux, Windows) or COMMAND (Mac OS X) exposes additional formal content.
• Dockable panels (e.g. Output, Symbols) are managed as independent windows by jEdit, which also allows multiple instances.
• Formal output (in popups etc.) may be explored recursively, using the same techniques as in the editor source buffer.
• The prover process and source files are managed on the editor side. The prover operates on timeless and stateless document content via Isabelle/Scala.
• Plugin options of jEdit (for the Isabelle plugin) give access to a selection of Isabelle/Scala options and its persistence preferences, usually with immediate effect on the prover back-end or editor front-end.
• The logic image of the prover session may be specified within Isabelle/jEdit, but this requires restart. The new image is provided automatically by the Isabelle build process.

Isabelle symbols and fonts

• Isabelle supports infinitely many symbols:
  α, β, γ, …
  ∀, ∃, ∨, ∧, ⟶, ⟷, …
  ≤, ≥, ⊓, ⊔, …
  ℵ, △, ∇, …
  \<foo>, \<bar>, \<baz>, …
  
• There are some special control symbols to modify the style of a single symbol:
  ⇩ subscript
  ⇧ superscript
  ⇣ subscript within identifier
  ⇡ superscript within identifier
  ❙ bold face
• A default mapping relates some Isabelle symbols to Unicode points (see $ISABELLE_HOME/etc/symbols and $ISABELLE_HOME_USER/etc/symbols).
• The IsabelleText font ensures that Unicode points are actually seen on the screen (or printer).
• Input methods:
  • use the Symbols dockable
  • copy/paste from decoded source files
  • copy/paste from prover output
  • completion provided by Isabelle plugin, e.g.
    

    name	abbreviation	symbol
    lambda	%	λ
    Rightarrow	=>	⇒
    Longrightarrow	==>	⟹
    And	!!	⋀
    equiv	==	≡
    forall	!	∀
    exists	?	∃
    longrightarrow	-->	⟶
    and	/\	∧
    or	\/	∨
    not	~	¬
    noteq	~=	≠
    in	:	∈
    notin	~:	∉
    sub	=_	⇩
    sup	=^	⇧
    isup	-_	⇣
    isub	-^	⇡
    bold	-.	❙

• NOTE: The above abbreviations refer to the input method. The logical notation provides ASCII alternatives that often coincide, but deviate occasionally.
• NOTE: Generic jEdit abbreviations or plugins perform similar source replacement operations; this works for Isabelle as long as the Unicode sequences coincide with the symbol mapping.
• NOTE: Raw Unicode characters within prover source files should be restricted to informal parts, e.g. to write text in non-latin alphabets. Mathematical symbols should be defined via the official rendering tables.
• NOTE: Control symbols may be applied to a region of selected text, either using the Symbols dockable or keyboard shortcuts.

Limitations and known problems

• Keyboard shortcuts C-PLUS and C-MINUS for adjusting the editor font size depend on platform details and national keyboards.
  Workaround: Use numeric keypad or rebind keys in the jEdit Shortcuts options dialog.
• Lack of dependency management for auxiliary files that contribute to a theory (e.g. ML_file).
  Workaround: Re-load files manually within the prover.
• Odd behavior of some diagnostic commands with global side-effects, like writing a physical file.
  Workaround: Avoid such commands.
• No way to delete document nodes from the overall collection of theories.
  Workaround: Restart whole Isabelle/jEdit session in worst-case situation.
• Some Linux desktop environments with extreme animation effects may disrupt Java 7 window placement and keyboard focus.
  Workaround: Disable such effects.
• The native MacOSX plugin for jEdit tends to be disruptive and is off by default. Enabling it might or might not improve the user experience.
  Workaround: Disable MacOSX plugin.
• Java 7 on MacOSX is officially supported on Lion and Mountain Lion, but not Snow Leopard. It usually works on the latter, although with a small risk of instabilities.
  Workaround: Update to OS X Mountain Lion.

Licenses and home sites of contributing systems

• Isabelle: BSD-style
• Poly/ML: LGPL
  http://www.polyml.org
• Scala: BSD-style
  http://www.scala-lang.org
• jEdit: GPL (with special cases)
  http://www.jedit.org
• JFreeChart: LGPL
  http://www.jfree.org
• Lobo/Cobra: GPL and LGPL
  http://lobobrowser.org