frontend/parse.c, allow nested `indexing', for example foo[bar[n]]

.control
compose ex1 values 111 222 333
compose ex2 values 1 2 3
print ex1 ex2 ex1[ex2[1]]
.endc

src/frontend/parse-bison.y

@@ -82,7 +82,7 @@
 
 %token <num>  TOK_NUM
 %token <str>  TOK_STR
-%token        TOK_LE TOK_GE TOK_NE TOK_LRANGE TOK_RRANGE
+%token        TOK_LE TOK_GE TOK_NE
 
 %type  <pnode>   exp exp_list one_exp
 
@@ -99,7 +99,6 @@
 %left   NEG      /* negation--unary minus */
 %right  '^'      /* exponentiation */
 %left   '[' ']'
-%left   TOK_LRANGE TOK_RRANGE
 
 %initial-action      /* initialize yylval */
 {
@@ -164,7 +163,7 @@ exp:
   | exp '|' exp                       { $$ = mkbnode(PT_OP_OR,  $1, $3); }
 
   | exp '[' exp ']'                   { $$ = mkbnode(PT_OP_INDX,  $1, $3); }
-  | exp TOK_LRANGE exp TOK_RRANGE     { $$ = mkbnode(PT_OP_RANGE, $1, $3); }
+  | exp '[' '['  exp ']' ']'          { $$ = mkbnode(PT_OP_RANGE, $1, $4); }
   | exp '?' exp ':' exp               { $$ = mkbnode(PT_OP_TERNARY,$1,
                                                      mkbnode(PT_OP_COMMA,$3,$5)); }
 ;

src/frontend/parse.c

@@ -606,18 +606,8 @@ PPlex(YYSTYPE *lvalp, struct PPltype *llocp, char **line)
     switch (*sbuf) {
 
     case '[':
-        if (sbuf[1] == '[') {
-            lexer_return(TOK_LRANGE, 2);
-        } else {
-            lexer_return(*sbuf, 1);
-        }
-
     case ']':
-        if (sbuf[1] == ']') {
-            lexer_return(TOK_RRANGE, 2);
-        } else {
-            lexer_return(*sbuf, 1);
-        }
+        lexer_return(*sbuf, 1);
 
     case '>':
     case '<':