More parameter checks (#1485)

Checks added to 'If', 'While', and 'Throw', "ToExpression". 

We start to handle 'argb' tag, "between x and y".

Some linting and small document corrections were done.

Author: rocky

mathics/builtin/atomic/strings.py

@@ -13,7 +13,7 @@
 
 from mathics_scanner.errors import SyntaxError
 
-from mathics.core.atoms import Integer, Integer0, Integer1, String
+from mathics.core.atoms import Integer, Integer1, String
 from mathics.core.attributes import A_LISTABLE, A_PROTECTED
 from mathics.core.builtin import Builtin, Predefined, PrefixOperator
 from mathics.core.convert.expression import to_mathics_list
@@ -331,7 +331,7 @@ class CharacterEncodings(Predefined):
     https://reference.wolfram.com/language/ref/\$CharacterEncodings.html</url>
 
     <dl>
-      <dt>'\\$CharacterEncodings'
+      <dt>'\$CharacterEncodings'
       <dd>stores the list of available character encodings.
     </dl>
 
@@ -739,7 +739,7 @@ class ToExpression(Builtin):
     https://reference.wolfram.com/language/ref/ToExpression.html</url>
     <dl>
       <dt>'ToExpression'[$input$]
-      <dd>interprets a given string as Mathics input.
+      <dd>interprets a given string as Mathics3 input.
 
       <dt>'ToExpression'[$input$, $form$]
       <dd>reads the given input in the specified $form$.
@@ -773,11 +773,11 @@ class ToExpression(Builtin):
     """
     attributes = A_LISTABLE | A_PROTECTED
 
+    # Set checking that the between one and three arguments are allowed.
+    eval_error = Builtin.generic_argument_error
+    expected_args = range(1, 4)
+
     messages = {
-        "argb": (
-            "`1` called with `2` arguments; "
-            "between `3` and `4` arguments are expected."
-        ),
         "interpfmt": (
             "`1` is not a valid interpretation format. "
             "Valid interpretation formats include InputForm "
@@ -844,13 +844,6 @@ def eval(self, seq, evaluation: Evaluation):
 
         return result
 
-    def eval_empty(self, evaluation: Evaluation):
-        "ToExpression[]"
-        evaluation.message(
-            "ToExpression", "argb", "ToExpression", Integer0, Integer1, Integer(3)
-        )
-        return
-
 
 class ToString(Builtin):
     """

mathics/builtin/codetables.py

@@ -5,7 +5,7 @@
 """
 
 # an (incomplete) list of ISO 639-3 language codes. these codes are used in Extended Open Multilingual Wordnet
-# (see e.g. http://compling.hss.ntu.edu.sg/omw/summx.html) and in Tesseract (see e.g.
+# (see e.g. http://compiling.hss.ntu.edu.sg/omw/summx.html) and in Tesseract (see e.g.
 # https://github.com/tesseract-ocr/tessdata). For the complete list, see http://www-01.sil.org/iso639-3/codes.asp
 
 iso639_3 = {

mathics/builtin/numeric.py

@@ -713,7 +713,7 @@ class Round(Builtin):
     eval_error = Builtin.generic_argument_error
     expected_args = (1, 2)
 
-    # For now, we handle Rounding Complex numnbers as rules.
+    # For now, we handle Rounding Complex numbers as rules.
     # In the future consider folding this into the code.
     rules = {
         "Round[expr_Complex]": "Round[Re[expr], 1] + I * Round[Im[expr], 1]",

mathics/builtin/procedural.py

@@ -55,9 +55,13 @@ class Abort(Builtin):
      = $Aborted
     """
 
+    # Set checking that the no arguments are allowed.
+    # eval_error = Builtin.generic_argument_error
+    # expected_args = 0
+
     summary_text = "generate an abort"
 
-    def eval(self, evaluation: Evaluation):
+    def eval(self, evaluation: Evaluation):  # pylint: disable=unused-argument
         "Abort[]"
 
         raise AbortInterrupt
@@ -78,13 +82,17 @@ class Break(Builtin):
      = 11
     """
 
+    # Set checking that the no arguments are allowed.
+    # eval_error = Builtin.generic_argument_error
+    # expected_args = 0
+
     messages = {
         "nofwd": "No enclosing For, While, or Do found for Break[].",
     }
 
     summary_text = "exit a 'For', 'While', or 'Do' loop"
 
-    def eval(self, evaluation: Evaluation):
+    def eval(self, evaluation: Evaluation):  # pylint: disable=unused-argument
         "Break[]"
 
         raise BreakInterrupt
@@ -125,6 +133,10 @@ class Catch(Builtin):
 
     attributes = A_HOLD_ALL | A_PROTECTED
 
+    # Set checking that the between one and three arguments are allowed.
+    eval_error = Builtin.generic_argument_error
+    expected_args = range(1, 4)
+
     summary_text = "handle an exception raised by a 'Throw'"
 
     def eval_expr(self, expr, evaluation):
@@ -297,7 +309,7 @@ class Do(IterationFunction):
     allow_loopcontrol = True
     summary_text = "evaluate an expression looping over a variable"
 
-    def get_result(self, items):
+    def get_result(self, _items):
         return SymbolNull
 
 
@@ -377,15 +389,32 @@ class If(Builtin):
     >> If[False, a] //FullForm
      = Null
 
-    You might use comments (inside '(*' and '*)') to make the branches of 'If'
+    You might use comments inside '(*' and '*)' to make the branches of 'If'
     more readable:
     >> If[a, (*then*) b, (*else*) c];
+
+
+    Since one or more arguments to a boolean operation could be symbolic, it is\
+    possible that an 'If' cannot be evaluated. For example:
+
+    >> Clear[a, b]; If [a < b, a, b]
+     = If[a < b, a, b]
+
+    To handle this, 'If' takes an optional fourth parameter:
+
+    >> If [a < b, a, b, "I give up"]
+     = I give up
+
     """
 
-    summary_text = "if-then-else conditional expression"
     # This is the WR summary: "test if a condition is true, false, or
     # of unknown truth value"
     attributes = A_HOLD_REST | A_PROTECTED
+
+    # Set checking that the number of arguments required between 2 and 4.
+    eval_error = Builtin.generic_argument_error
+    expected_args = range(2, 5)
+
     summary_text = "test if a condition is true, false, or of unknown truth value"
 
     def eval(self, condition, t, evaluation):
@@ -429,9 +458,13 @@ class Interrupt(Builtin):
      = $Aborted
     """
 
+    # Set checking that the no arguments are allowed.
+    # eval_error = Builtin.generic_argument_error
+    # expected_args = 0
+
     summary_text = "interrupt evaluation and return '$Aborted'"
 
-    def eval(self, evaluation: Evaluation):
+    def eval(self, evaluation: Evaluation):  # pylint: disable=unused-argument
         "Interrupt[]"
 
         raise AbortInterrupt
@@ -460,7 +493,7 @@ class Pause(Builtin):
     # Number of timeout polls per second that we perform in looking
     # for a timeout.
 
-    def eval(self, n, evaluation: Evaluation):
+    def eval(self, n, evaluation: Evaluation):  # pylint: disable=unused-argument
         "Pause[n_]"
         try:
             sleep_time = valid_time_from_expression(n, evaluation)
@@ -504,7 +537,7 @@ class Return(Builtin):
 
     summary_text = "return from a function"
 
-    def eval(self, expr, evaluation: Evaluation):
+    def eval(self, expr, evaluation: Evaluation):  # pylint: disable=unused-argument
         "Return[expr_]"
         raise ReturnInterrupt(expr)
 
@@ -594,17 +627,23 @@ class Throw(Builtin):
      = Hold[Throw[1]]
     """
 
+    # Set checking that the number of arguments required is one or two. WMA uses 1..3.
+    eval_error = Builtin.generic_argument_error
+    expected_args = (1, 2)
+
     messages = {
         "nocatch": "Uncaught `1` returned to top level.",
     }
 
     summary_text = "throw an expression to be caught by a surrounding 'Catch'"
 
-    def eval(self, value, evaluation: Evaluation):
+    def eval(self, value, evaluation: Evaluation):  # pylint: disable=unused-argument
         "Throw[value_]"
         raise WLThrowInterrupt(value)
 
-    def eval_with_tag(self, value, tag, evaluation: Evaluation):
+    def eval_with_tag(
+        self, value, tag, evaluation: Evaluation
+    ):  # pylint: disable=unused-argument
         "Throw[value_, tag_]"
         raise WLThrowInterrupt(value, tag)
 
@@ -692,11 +731,15 @@ class While(Builtin):
      = 3
     """
 
-    summary_text = "evaluate an expression while a criterion is true"
     attributes = A_HOLD_ALL | A_PROTECTED
+    # Set checking that the number of arguments required is one.
+    eval_error = Builtin.generic_argument_error
+    expected_args = (1, 2)
+
     rules = {
         "While[test_]": "While[test, Null]",
     }
+    summary_text = "evaluate an expression while a criterion is true"
 
     def eval(self, test, body, evaluation):
         "While[test_, body_]"

mathics/builtin/quantities.py

@@ -314,7 +314,7 @@ class QuantityQ(Test):
         https://reference.wolfram.com/language/ref/QuantityQ.html</url>
         <dl>
           <dt>'QuantityQ'[$expr$]
-          <dd>return 'True' if $expr$ is a valid <url>:'Quantity':/doc/reference-of-built-in-symbols/units-and-quantities
+          <dd>return 'True' if $expr$ is a valid <url>:Quantity:/doc/reference-of-built-in-symbols/units-and-quantities
     /quantity/</url> with valid arguments, and 'False' otherwise.
         </dl>
 

mathics/core/builtin.py

@@ -204,7 +204,7 @@ def eval_with_options(x, evaluation: Evaluation, options: dict):
     defaults: Dict[Optional[int], str] = {}
 
     # Number of arguments expected. -1 is used for arbitrary number.
-    expected_args: Union[int, Tuple[int, int]] = -1
+    expected_args: Union[int, Tuple[int, int], range] = -1
 
     formats: Dict[str, Any] = {}
     messages: Dict[str, Any] = {}
@@ -473,6 +473,15 @@ def generic_argument_error(self, invalid, evaluation: Evaluation):
                     Integer(expected_args1),
                     Integer(expected_args2),
                 )
+        elif isinstance(self.expected_args, range):
+            evaluation.message(
+                name,
+                "argb",
+                Symbol(name),
+                Integer(got_arg_count),
+                Integer(self.expected_args.start),
+                Integer(self.expected_args.stop - 1),
+            )
         else:
             if self.expected_args == 1:
                 evaluation.message(name, "argx", Symbol(name), Integer(got_arg_count))

mathics/core/expression.py

@@ -1373,7 +1373,7 @@ def rules():
                         result._timestamp_cache(evaluation)
                     return result, False
                 else:
-                    return result, True
+                    return result, result is not SymbolAborted
 
         # Step 7: If we are here, is because we didn't find any rule that
         # matches the expression.