4.5.1 Parser

The parser is available under the (rpc compiler parser) module. The main procedure, rpc-language->sexp, reads XDR/RPC language descriptions and returns the abstract syntax tree (AST) in the form of an S-expression. The AST can be shown using the --intermediate option of the grpc-compile command-line tool (see Invoking grpc-compile). Below is an illustration of the mapping between the XDR/RPC language and the S-exp representation.

     const SIZE = 10;
     struct foo
     {
       int x;
       enum { NO = 0, YES = 1 } y;
       float z[SIZE];
     };

... yields:

     (define-constant "SIZE" 10)
     (define-type
       "foo"
       (struct
         ("x" "int")
         ("y" (enum ("NO" 0) ("YES" 1)))
         ("z" (fixed-length-array "float" "SIZE"))))

The behavior of the parser can be controlled using the *parser-options* parameter object:

Source location information is attached to the S-expressions returned by rpc-language->sexp. It can be queried using the procedures below. Note that not-only top-level S-expressions (such as define-type or define-constant expressions) can be queried, but also sub-expressions, e.g., the enum S-expression above.

In case of parse errors or other compiler errors, a &compiler-error error condition (or an instance of a sub-type thereof) may be raise.