Finish the parser

main.rkt

@@ -30,13 +30,13 @@
    ["/" (token-DIV)]
    ["&" (token-AND)]
    ["|" (token-OR)]
-   [(or "<" "<=" "==" "~=" ">=" ">") (token-RELOP (string->symbol lexeme))]
+   ["<" (token-LBRAK)]
+   [">" (token-RBRAK)]
+   [(or "<=" "==" "~=" ">=") (token-RELOP (string->symbol lexeme))]
    ["(" (token-LPAREN)]
    [")" (token-RPAREN)]
    ["{" (token-LBRAC)]
    ["}" (token-RBRAC)]
-   ["<" (token-LBRAK)]
-   [">" (token-RBRAK)]
    [";" (token-SEMICOLON)]
    [(+ numeric) (token-NUM (string->number  lexeme))]
    [(: alphabetic (* (or alphabetic numeric #\_))) (token-VAR (string->symbol lexeme))]
@@ -44,18 +44,23 @@
 
 (define core/parser
   (parser
-   [start expr]
+   [start program]
    [end EOF]
    [tokens core/empty-tokens core/tokens]
    [precs
-    (nonassoc IN DOT)
+    (nonassoc IN DOT OF ARROW)
+    (nonassoc SEMICOLON)
     (right OR)
     (right AND)
-    (right RELOP)
+    (right RELOP LBRAK RBRAK)
     (left ADD MINUS)
     (left MULT DIV)]
-   [error void]
+   [error (λ (tok-ok? tok-name tok-value)
+            (error (format "Token Ok?: ~a\nToken name: ~a\nToken value: ~a" tok-ok? tok-name tok-value)))]
    [grammar
+    [program [(sc) (list $1)]
+             [(program SEMICOLON sc) (cons $3 $1)]]
+    [sc [(VAR vars ASSN expr) (list 'define (cons $1 (reverse $2)) $4)]]
     [expr [(expr ADD expr) (list '+ $1 $3)]
           [(expr MINUS expr) (list '- $1 $3)]
           [(LET defns IN expr) (list $1 (reverse $2) $4)]
@@ -63,8 +68,11 @@
           [(expr OR expr) (list 'or $1 $3)]
           [(expr AND expr) (list 'and $1 $3)]
           [(expr RELOP expr) (list $2 $1 $3)]
+          [(expr LBRAK expr) (list '< $1 $3)]
+          [(expr RBRAK expr) (list '> $1 $3)]
           [(expr DIV expr) (list '/ $1 $3)]
-          [(LAM vars DOT expr) (list 'λ (reverse $2) $4)]
+          [(LAM vars1 DOT expr) (list 'λ (reverse $2) $4)]
+          [(CASE expr OF alts) (list 'case $2 (reverse $4))]
           [(expr0) $1]]
     [expr0 [(expr0 aexpr) (list $1 $2)]
            [(aexpr) $1]]
@@ -75,5 +83,15 @@
     [defns [(defns SEMICOLON defn) (cons $3 $1)]
            [(defn) (list $1)]]
     [defn [(VAR ASSN expr) (list $1 $3)]]
-    [vars [(VAR) (list $1)]
-          [(vars VAR) (cons $2 $1)]]]))
+    [vars [() (list)]
+          [(vars VAR) (cons $2 $1)]]
+    [vars1 [(vars VAR) (cons $2 $1)]]
+    [alt [(LBRAK NUM RBRAK vars ARROW expr) (list 'branch $2 (reverse $4) $6)]]
+    [alts [(alt) (list $1)]
+          [(alts SEMICOLON alt) (cons $3 $1)]]]))
+
+(define (parse-from-port p)
+  (core/parser (λ () (core/lexer p))))
+
+(define (parse-from-string s)
+  (parse-from-port (open-input-string s)))