1 (*===----------------------------------------------------------------------=== 2 * Abstract Syntax Tree (aka Parse Tree) 3 *===----------------------------------------------------------------------===*) 4 5 (* expr - Base type for all expression nodes. *) 6 type expr = 7 (* variant for numeric literals like "1.0". *) 8 | Number of float 9 10 (* variant for referencing a variable, like "a". *) 11 | Variable of string 12 13 (* variant for a unary operator. *) 14 | Unary of char * expr 15 16 (* variant for a binary operator. *) 17 | Binary of char * expr * expr 18 19 (* variant for function calls. *) 20 | Call of string * expr array 21 22 (* variant for if/then/else. *) 23 | If of expr * expr * expr 24 25 (* variant for for/in. *) 26 | For of string * expr * expr * expr option * expr 27 28 (* variant for var/in. *) 29 | Var of (string * expr option) array * expr 30 31 (* proto - This type represents the "prototype" for a function, which captures 32 * its name, and its argument names (thus implicitly the number of arguments the 33 * function takes). *) 34 type proto = 35 | Prototype of string * string array 36 | BinOpPrototype of string * string array * int 37 38 (* func - This type represents a function definition itself. *) 39 type func = Function of proto * expr 40
