Programming%20in%20Several%20Dimensions

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Programming in Several Dimensions

• Paul Lyons
• Massey University

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Textual Languages are One-dimensional
How about programs?
Computers are sequential.
Input devices Output devices Memory
addresses Accumulator Buses Parsers
Flow of control Sequential syntax Tree-structured
semantics Declarations Tree-structured Inverted
w.r.t. procedures I/O Asynchronous
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Computers Support Multi-dimensionality
Power Easy 2-D input High-res 2-D and 3-D
graphic output Multiple window support
Synchronous updating Hyperlinks
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A Multi-dimensional Language
Desiderata
High-level
Multiple views Non-sequential access Easy
editing Efficient space use
Mid-level
Control relationships Text where
appropriate Graphics where appropriate
Low-level
Group related concepts Purge brackets
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HyperPascal
Visualisations
hyperlinks
Action Tree
Scope Tree
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HyperPascal
Visualisations
hyperlinks
Action Tree
Scope Tree
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HyperPascal
Visualisations
hyperlinks
Scope Tree
Action Tree
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HyperPascal
Visualisations
hyperlinks
Scope Tree
Action Tree
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HyperPascal
Structure Template Visualisation
Dot-and-caret notation
Pictorial notation
new(newNode) newNode.data x if L nil
then begin L newNode.next L
newNode end else begin parent nil
thisNode L status running while
status running do begin if
(thisNode.data gt x) or (thisNode nil)_then
begin newNode.next thisNode if
parent nil then L newNode else
parent.next newNode status
finished end then clause else begin
parent thisNode thisNode
thisNode.next end if end end
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new(newNode) newNode.data x if L nil
then begin newNode.next L L
newNode end else begin L isnt nil parent
nil thisNode L status running
while status running do begin if
(thisNode.data gt x) or (thisNode nil)_then
begin newNode.next thisNode if
parent nil then L newNode else
parent.next newNode status
finished end then clause else begin the
node goes somewhere else parent
thisNode thisNode thisNode.next end
if end end
HyperPascal
Structure Template Visualisation
Dot-and-caret notation
Pictorial notation
new(newNode) newNode.data x if L nil
then begin L newNode.next L
newNode end else begin parent nil
thisNode L status running while
status running do begin if
(thisNode.data gt x) or (thisNode nil)_then
begin newNode.next thisNode if
parent nil then L newNode else
parent.next newNode status
finished end then clause else begin
parent thisNode thisNode
thisNode.next end if end end

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new(newNode) newNode.data x if L nil
then begin newNode.next L L
newNode end else begin L isnt nil parent
nil thisNode L status running
while status running do begin if
(thisNode.data gt x) or (thisNode nil)_then
begin newNode.next thisNode if
parent nil then L newNode else
parent.next newNode status
finished end then clause else begin the
node goes somewhere else parent
thisNode thisNode thisNode.next end
if end end
parent thisNode thisNode
thisNode.next
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HyperPascal
Structure Template Visualisation
Dot-and-caret notation
Pictorial notation
new(newNode) newNode.data x if L nil
then begin L newNode.next L
newNode end else begin parent nil
thisNode L status running while
status running do begin if
(thisNode.data gt x) or (thisNode nil) then
begin newNode.next thisNode if
parent nil then L newNode else
parent.next newNode status
finished end then clause else begin
parent thisNode thisNode
thisNode.next end if end end
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HyperPascal
Pictorial declarations
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HyperPascal
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HyperPascal
Easy-to-draw pictures
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HyperPascal
Easy-to-draw pictures
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HyperPascal
Easy-to-draw pictures
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HyperPascal
Easy-to-draw pictures
gtx
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HyperPascal
Easy-to-draw pictures
gtx
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HyperPascal
Easy-to-draw pictures
gtx
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HyperPascal
Easy-to-draw pictures
gtx
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HyperPascal
Easy-to-draw pictures
x
gtx
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HyperPascal
Easy-to-draw pictures
if thisNode ltgt nil then if thisNode.data gt x
then generate after-picture1
else thisNode ltgt nil and thisNode.data ltx
generate after-picture 2
else thisNode nil
generate after-picture 3
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HyperPascal
Three-layer architecture
Draw commands
User actions
(undistorted coordinates)
(undistorted coordinates)
Object association information
Redraw messages
(coordinate-free)
(coordinate-free)
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HyperPascal
FIN
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HyperPascal
Easy-to-draw pictures
if thisNode ltgt nil then if thisNode.data gt x
then generate after-picture1 else
thisNode.data ltx generate after-picture
2 else thisNode nil generate after-picture
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if L ltgt nil then if L.data gt x then generate
after-picture1 else L.data ltx generate
after-picture 2 else L nil
if L ltgt nil then if L.data gt x then generate
after-picture1 else L.data ltx generate
after-picture 2