Saturday, December 6, 2014

Progress - Initial Iteration

The first iteration is progressing. As much as I would like type declarations and functions be very similar, they are currently very distinct. This is for simplicity and the whole "don't get fancy" focus. The current language is dead simple (not lisp dead simple, but dead simple compared to what I'd like eventually):

program ::= (type-decl | function-decl)*
type-decl ::= id+ :> enum { comma-delimited-id-list
function-decl ::= phrase-part+ => id+ { statement* }
phrase-part ::= id | parameter-decl
parameter-decl ::= '(' id+ : id+ ')'
statement ::= id+ ;

The rest of the work is done in the second step of the parser, the part that we're focusing on this time around. That part takes the various statements and performs bottom-up parsing on them using the type declarations from the first (conventional) step of the parser. The void type is used to define the start rule for statements, and other rules will need to be used to help deal with potential ambiguities (like preferring an id literal over a parameter reference).

Otherwise, it should proceed pretty much like any other bottom-up parsing approach, albeit providing an extensible syntax while demanding nothing more from programmers than they're used to - declaring and annotating types. Currently, the first step of the parser is dev-done. 

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