Study 1

In order to study some implications of a purely AST-centric IDE I wrote a prototype in Java (download it here).

It is an IDE for a tiny procedural language which I called 'Simple'. Here are the main features of Simple:

Scalar variables: Types are integer, floating point number, boolean, and string. Not type-safe.
Operators: '+', '-', '*', '/', '>', '>=', '<', '<=', '>', '>=', '=', '!='
Functions with scalar result and arbitrary but fixed number of arguments.
Assignment statement
If, elseif, and else statements
While statement
Return statement
Console output
Console input

The screen shot shows some of the advantages of an AST-centric IDE:

Graphical non-textual visualization of the tree.
Expanding/collapsing of tree nodes.
Visualization mixes text (in different fonts and colors) and icons.
Pretty line wrapping.
Dynamic line wrapping: Statements will be wrapped around if the width of the window shrinks.

The AST is stored in an ASCII file in a very compact format (not XML). Here is the example from the screen shot:

b
(
f:1.fibonacci:x
(
i:LT:v-1:L2
(
r:v-2
)
e
(
a:f1:f-3.1:1:SUB:v-3:L1
a:f2:f-4.1:1:SUB:v-4:L2
r:ADD:v-2:v-1
)
)
a:v:I0
w:GE:v-1:I0
(
t:-2:"Enter a number: "
p:ADD:"fibonacci(":ADD:v-3:ADD:")=":f-4.1:1:v-3
)
)

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(C) 2005-2007 Franz-Josef Elmer. All rights reserved. Last modified: 5/6/2007