Adding basic parser of rash language

rash-lang.rkt

@@ -0,0 +1,51 @@
+#lang racket/base
+
+(require syntax/readerr
+         (prefix-in rash: "rash.rkt"))
+
+(define (rash-read in)
+  (syntax->datum (rash-read-syntax #f in)))
+
+(define (rash-read-syntax src in)
+  (define-values (start-line start-col start-pos) (port-next-location in))
+  (define (list->rash-syntax l span)
+    (datum->syntax #f
+                   (cons 'start l)
+                   (vector src start-line start-col start-pos span)))
+
+  (let loop ([words '()]
+             [delta 0])
+    (define-values (line col pos) (port-next-location in))
+    (cond
+     [(regexp-try-match #px"^[[:alnum:]]+" in) =>
+      (λ (r)
+         (define m (bytes->string/utf-8 (car r)))
+         (define len (string-length m))
+         (define word (datum->syntax #f m (vector src line col pos len)))
+         (loop (cons word words) len))]
+     [(regexp-try-match #px"^\n" in) => (λ (m) (list->rash-syntax
+                                                (reverse words)
+                                                delta))]
+     [(regexp-try-match #px"^[ \t]+" in) => (λ (r)
+                                               (define m
+                                                 (bytes->string/utf-8 (car r)))
+                                               (displayln m)
+                                               (loop words (string-length m)))]
+     [(eof-object? (peek-char in)) (list->rash-syntax (reverse words) delta)]
+     [else (raise-read-error
+            (string-append "Unknown character " (read-char in))
+            src line col pos 1)])))
+
+(module+ test
+  (require rackunit)
+
+  (define (2port str)
+    (open-input-string str))
+
+  (test-case
+   "Read alphanumeric words with EOF"
+   (check equal? '(start "echo" "hello1") (rash-read (2port "echo hello1"))))
+
+  (test-case
+   "Read string with newline"
+   (check equal? '(start "echo") (rash-read (2port "echo\n")))))