modelize_property: implement special validity rules for operators

Signed-off-by: Jean Privat <jean@pryen.org>

diff --git a/src/modelize/modelize_property.nit b/src/modelize/modelize_property.nit
index 9cc9580..c0d3890 100644 (file)
--- a/src/modelize/modelize_property.nit
+++ b/src/modelize/modelize_property.nit
@@ -790,11 +790,17 @@ redef class AMethPropdef
                        name = amethodid.collect_text
                        name_node = amethodid
 
-                       if name == "+" and self.n_signature.n_params.length == 0 then
+                       var arity = self.n_signature.n_params.length
+                       if name == "+" and arity == 0 then
                                name = "unary +"
-                       end
-                       if name == "-" and self.n_signature.n_params.length == 0 then
+                       else if name == "-" and arity == 0 then
                                name = "unary -"
+                       else
+                               if amethodid.is_binary and arity != 1 then
+                                       modelbuilder.error(self.n_signature, "Syntax Error: binary operator `{name}` requires exactly one parameter; got {arity}.")
+                               else if amethodid.min_arity > arity then
+                                       modelbuilder.error(self.n_signature, "Syntax Error: `{name}` requires at least {amethodid.min_arity} parameter(s); got {arity}.")
+                               end
                        end
                end
 
@@ -868,6 +874,9 @@ redef class AMethPropdef
                        end
                end
 
+               var accept_special_last_parameter = self.n_methid == null or self.n_methid.accept_special_last_parameter
+               var return_is_mandatory = self.n_methid != null and self.n_methid.return_is_mandatory
+
                # Retrieve info from the signature AST
                var param_names = new Array[String] # Names of parameters from the AST
                var param_types = new Array[MType] # Types of parameters from the AST
@@ -941,6 +950,14 @@ redef class AMethPropdef
                # In `new`-factories, the return type is by default the classtype.
                if ret_type == null and mpropdef.mproperty.is_new then ret_type = mclassdef.mclass.mclass_type
 
+               # Special checks for operator methods
+               if not accept_special_last_parameter and mparameters.not_empty and mparameters.last.is_vararg then
+                       modelbuilder.error(self.n_signature.n_params.last, "Error: illegal variadic parameter `{mparameters.last}` for `{mpropdef.mproperty.name}`.")
+               end
+               if ret_type == null and return_is_mandatory then
+                       modelbuilder.error(self.n_methid, "Error: mandatory return type for `{mpropdef.mproperty.name}`.")
+               end
+
                msignature = new MSignature(mparameters, ret_type)
                mpropdef.msignature = msignature
                mpropdef.is_abstract = self.get_single_annotation("abstract", modelbuilder) != null
@@ -1022,6 +1039,56 @@ redef class AMethPropdef
        end
 end
 
+redef class AMethid
+       # Is a return required?
+       #
+       # * True for operators and brackets.
+       # * False for id and assignment.
+       fun return_is_mandatory: Bool do return true
+
+       # Can the last parameter be special like a vararg?
+       #
+       # * False for operators: the last one is in fact the only one.
+       # * False for assignments: it is the right part of the assignment.
+       # * True for ids and brackets.
+       fun accept_special_last_parameter: Bool do return false
+
+       # The minimum required number of parameters.
+       #
+       # * 1 for binary operators
+       # * 1 for brackets
+       # * 1 for assignments
+       # * 2 for bracket assignments
+       # * 0 for ids
+       fun min_arity: Int do return 1
+
+       # Is the `self` a binary operator?
+       fun is_binary: Bool do return true
+end
+
+redef class AIdMethid
+       redef fun return_is_mandatory do return false
+       redef fun accept_special_last_parameter do return true
+       redef fun min_arity do return 0
+       redef fun is_binary do return false
+end
+
+redef class ABraMethid
+       redef fun accept_special_last_parameter do return true
+       redef fun is_binary do return false
+end
+
+redef class ABraassignMethid
+       redef fun return_is_mandatory do return false
+       redef fun min_arity do return 2
+       redef fun is_binary do return false
+end
+
+redef class AAssignMethid
+       redef fun return_is_mandatory do return false
+       redef fun is_binary do return false
+end
+
 redef class AAttrPropdef
        redef type MPROPDEF: MAttributeDef