| Erick Tryzelaar | f119765 | 2010-03-08 19:32:27 +0000 | [diff] [blame] | 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 binary operator. *) |
| 14 | | Binary of char * expr * expr |
| 15 | |
| 16 | (* variant for function calls. *) |
| 17 | | Call of string * expr array |
| 18 | |
| 19 | (* proto - This type represents the "prototype" for a function, which captures |
| 20 | * its name, and its argument names (thus implicitly the number of arguments the |
| 21 | * function takes). *) |
| 22 | type proto = Prototype of string * string array |
| 23 | |
| 24 | (* func - This type represents a function definition itself. *) |
| 25 | type func = Function of proto * expr |