#Quasar Syntax
Quasar is a language whose idioms may be described completely by s-expressions. Here is a listing of the basic language specifications for now.
##Special forms
-
if (TODO) -
(if cond then else)ifevaluatesthenifcondis true. Otherwise, it evaluteselseifelseis not null. -
while (TODO) -
(while cond then)As usual, while is a loop that evaluatescondand executes the body if it evaluates totrue. -
set (TODO) -
(set symbol val)Instead of explicitly requiring type declarations,setcan bind a symbol to a literal or an object. -
fn -
(fn args[as a list] sexp)fn binds and makes available for execution a certain s-expression (list).
-
(set some-fn (fn ...))then(some-fn args)is a function declaration. -
fnreturns a reference to a function, so anonymous functions can be declared as such:((fn ...) args)
##Comments
Single-line (#) or multi-lined (###foo###) with match-rules in the parser to discard. (TODO)
##Integers
Standard 0-9 (implemented). For alternative base systems, these can be generated by user-defined functions and strings.
##Floating point
[0-9]+ "." [0-9]+ TODO: different orders of precision.
##Booleans
true or false, case insensitive. TODO: implement logical operators. (probably functions too)
##Symbols
a-zA-Z symbols accepted. Like some other languages, symbols may have a "text representation".
##Typecasting
Each of the elementary literals outlined above can be recasted with functions defined within the language (and not unique to the low-level specs of the language.)
#AST Parsing
The PEG.js parser-generator can explicitly generate a parser which will output a AST and perform intermediate tasks (preprocessing specific forms). With a JSON-like AST, we can crawl and execute the forms of our program.
The generated AST from PEG.js is in JSON, and can be crawled by any language that can parse JSON, including javascript itself.
##Example AST
<factorial 10>
Output: { "type": "program", "body": [ { "type": "list", "body": [ { "type": "symbol", "body": "factorial" }, { "type": "int", "body": 10 } ] } ] }