archives

Minimal set of operators for APL/J like language

Is there any work proposing a minimal set of orthogonal operators to make an APL like language?

APL, J, et. al seem to mix what in other languages most people (or at least I) would call core language vs. library functions. I'm interested in the core language. In particular, it's not clear to me which are the adverbs required to operate on different kinds of array slices.

Context free grammar for shapes in a 2d grid?

I was playing around with defining grammar productions rules for shapes in a 2d grid. Seems like using this type of scheme to generate complex shapes is very easy. But going the opposite direction and recognizing the language is impossible. If one has a grid consisting of cells filled with all terminal characters, if an arbitrary cell is chosen and the attempt is made to derive a parse tree from this cell, the ambiguity mounts quickly. Basically, any cell picked will give a different parse tree.

Thinking about it, this approach should generalize to grammars applied to graphs. Googling about for a bit and viewing the bibliograph statistics shows that there was some work done in this area in the late 90's but has since entirely disappeared:

Bibligraph stats for "graph grammar"

So, is anyone familiar with this area? Why did work in this area (almost) completely stop? Looks like some work was oriented toward parsing visual programming languages...