[parser] Add handling of block arguments.

Author: samdphillips

smalltalk-parser/parse/block.rkt

@@ -4,6 +4,7 @@
          racket/function
          racket/unit
          smalltalk/reader
+         (submod smalltalk/reader for-pipes)
          "interface.rkt"
          "util.rkt")
 
@@ -14,7 +15,12 @@
   (export st:block^)
 
   (define st:block-args/p
-    (return/p null))
+    (or/p (do/p [args <- (many1/p st:block-argument/p)]
+                (or/p st:pipe/p
+                      (do/p [p <- st:double-pipe/p]
+                            (push/p (binary-selector (token-srcloc p) '\|))))
+                (return/p args))
+          (return/p null)))
 
   (define (make-block-stx lb rb args temps body)
     (quasisyntax/loc (build-source-location lb rb args temps body)

smalltalk-parser/parse/util.rkt

@@ -23,24 +23,27 @@
 (define st:binary-selector/p
   (token->syntax/p (satisfy/p binary-selector?)))
 
+(define st:block-argument/p
+  (token->syntax/p (satisfy/p block-argument?)))
+
 (define (st:delimiter/p type)
   (~> (conjoin
        delimiter?
        (lambda~> token-value (eq? type)))
       satisfy/p
       token->syntax/p))
 
-(define st:pipe/p
+(define/p st:pipe/p
   (satisfy/p (conjoin
-               binary-selector?
-               (lambda (tok)
-                 (eq? '\| (token-value tok))))))
+              binary-selector?
+              (lambda (tok)
+                (eq? '\| (token-value tok))))))
 
-(define st:double-pipe/p
+(define/p st:double-pipe/p
   (satisfy/p (conjoin
-               binary-selector?
-               (lambda (tok)
-                 (eq? '\|\| (token-value tok))))))
+              binary-selector?
+              (lambda (tok)
+                (eq? '\|\| (token-value tok))))))
 
 (define (st:opener/p s)
   (~> (conjoin

smalltalk-reader/reader.rkt

@@ -19,6 +19,14 @@
          opener?
          closer?)
 
+;; The pipe (vertical bar) character is part of the structural syntax and also
+;; an binary message selector.  Ideally the constructor should be private to the
+;; tokenizer, but it is provided here from a submodule because it is needed so the
+;; parser can synthesize and inject a token when handling the parsing of blocks.
+;; This is not part of the public interface, and could disappear if a better
+;; solution is found.
+(module* for-pipes #f (provide binary-selector))
+
 (require racket/match
          (prefix-in - syntax/readerr)
          syntax/srcloc