git pMerge branch 'main' of https://github.com/jsiek/deduce

rec_desc_parser.py

@@ -250,11 +250,14 @@ def parse_term_hi():
 
   elif token.type == 'LPAR':
     advance()
+    while_parsing = 'while parsing parenthesized term\n' \
+        + '\tterm ::= "(" term ")"\n'
+
     term = parse_term()
     if current_token().type != 'RPAR':
       error(meta_from_tokens(current_token(), current_token()),
             'expected closing parentheses, not\n\t' \
-            + current_token().value)
+            + current_token().value + '\n' + while_parsing)
     advance()
     return term
 
@@ -1307,10 +1310,17 @@ def parse_statement():
     name = parse_identifier()
     return Import(meta_from_tokens(token, previous_token()), name)
   elif token.type == 'PRINT':
+    while_parsing = 'while parsing\n' \
+        + '\tstatement ::= "print" term\n'
     advance()
-    subject = parse_term()
-    meta = meta_from_tokens(token, previous_token())
-    return Print(meta, subject)
+    try:
+        subject = parse_term()
+        meta = meta_from_tokens(token, previous_token())
+        return Print(meta, subject)
+    except Exception as e:
+        meta = meta_from_tokens(token, previous_token())
+        raise Exception(str(e) + '\n' + error_header(meta) + while_parsing)
+
   elif token.type == 'THEOREM' or token.type == 'LEMMA':
     return parse_theorem()
   elif token.type == 'UNION':

test/should-error/paren_term.pf

@@ -0,0 +1,9 @@
+import Nat
+import List
+
+function sum(List<Nat>) -> Nat {
+  sum([]) = 0
+  sum(node(x, xs)) = x + sum(xs)
+}
+
+print(sum, [1,2,3])

test/should-error/paren_term.pf.err

@@ -0,0 +1,8 @@
+./test/should-error/paren_term.pf:9.10-9.11: expected closing parentheses, not
+	,
+while parsing parenthesized term
+	term ::= "(" term ")"
+
+./test/should-error/paren_term.pf:9.1-9.10: while parsing
+	statement ::= "print" term
+