merge all cases

frontend/checkFunctionBodies.icl

 implementation module checkFunctionBodies
 
 import syntax, typesupport, parse, checksupport, utilities, checktypes, transform, predef //, RWSDebug
-import explicitimports, comparedefimp
+import explicitimports, comparedefimp, mergecases
 
 cIsInExpressionList		:== True
 cIsNotInExpressionList	:== False
@@ -516,9 +516,10 @@ checkExpression free_vars (PE_Case case_ident expr alts) e_input e_state e_info
 	# (pattern_expr, free_vars, e_state, e_info, cs) = checkExpression free_vars expr e_input e_state e_info cs
 	  (guards, _, pattern_variables, defaul, free_vars, e_state, e_info, cs) = check_guarded_expressions free_vars alts [] case_ident.id_name e_input e_state e_info cs
 	  (pattern_expr, binds, es_expr_heap) = bind_pattern_variables pattern_variables pattern_expr e_state.es_expr_heap
-	  (case_expr, es_expr_heap) = build_case guards defaul pattern_expr case_ident es_expr_heap
+	  (case_expr, es_var_heap, es_expr_heap, cs_error) = build_and_merge_case guards defaul pattern_expr case_ident e_state.es_var_heap es_expr_heap cs.cs_error
+	  cs = {cs & cs_error = cs_error}
 	  (result_expr, es_expr_heap) = buildLetExpression [] binds case_expr NoPos es_expr_heap
-	= (result_expr, free_vars, { e_state & es_expr_heap = es_expr_heap }, e_info, cs)
+	= (result_expr, free_vars, { e_state & es_var_heap = es_var_heap,  es_expr_heap = es_expr_heap }, e_info, cs)
 	
 where
 	check_guarded_expressions free_vars [g] pattern_variables case_name e_input=:{ei_expr_level} e_state e_info cs
@@ -617,7 +618,8 @@ where
 		# free_var = { fv_name = name, fv_info_ptr = var_info, fv_def_level = NotALevel, fv_count = 0 }
 		  (new_bound_var, expr_heap) = allocate_bound_var free_var expr_heap
 		  case_ident = { id_name = case_name, id_info = nilPtr }
-		  (new_case, expr_heap) = build_case patterns defaul (Var new_bound_var) case_ident expr_heap
+		  (new_case, var_store, expr_heap, cs_error) = build_and_merge_case patterns defaul (Var new_bound_var) case_ident var_store expr_heap cs.cs_error
+		  cs = {cs & cs_error = cs_error}
 		  new_defaul = insert_as_default new_case result_expr
 		= (NoPattern, pattern_scheme, (cons_optional opt_var pattern_variables), Yes (Yes free_var, new_defaul),
 			var_store, expr_heap, opt_dynamics, cs)
@@ -643,6 +645,59 @@ where
 			Yes defaul	-> Case { kees & case_default = Yes (insert_as_default to_insert defaul)}
 	insert_as_default _ expr = expr // checkWarning "pattern won't match"
 
+	build_and_merge_case patterns defaul expr case_ident var_heap expr_heap error_admin
+		# (expr, expr_heap)= build_case patterns defaul expr case_ident expr_heap
+		# (expr, var_heap, expr_heap) = share_case_expr expr var_heap expr_heap
+		= merge_case expr var_heap expr_heap error_admin
+
+	share_case_expr (Let lad=:{let_expr}) var_heap expr_heap
+		# (let_expr, var_heap, expr_heap) = share_case_expr let_expr var_heap expr_heap
+		= (Let {lad & let_expr = let_expr}, var_heap, expr_heap)
+	share_case_expr expr=:(Case {case_expr=Var var_ptr}) var_heap expr_heap
+		= (expr, var_heap, expr_heap)
+	share_case_expr (Case kees=:{case_expr}) var_heap expr_heap
+		# (free_var, var_heap) = allocate_free_var { id_name = "_case_var", id_info = nilPtr } var_heap
+		  (bound_var, expr_heap) = allocate_bound_var free_var expr_heap
+		  (case_expression, expr_heap) = bind_default_variable case_expr free_var (Case {kees & case_expr = Var bound_var}) expr_heap
+	 	= (case_expression, var_heap, expr_heap)
+	share_case_expr expr var_heap expr_heap
+		=  (expr, var_heap, expr_heap)
+
+	merge_case (Let lad=:{let_expr}) var_heap expr_heap error_admin
+		# (let_expr, var_heap, expr_heap, error_admin) = merge_case let_expr var_heap expr_heap error_admin
+		= (Let {lad & let_expr = let_expr}, var_heap, expr_heap, error_admin)
+	merge_case (Case kees) var_heap expr_heap error_admin
+		# cases	= map (make_case kees.case_expr) (split_patterns kees.case_guards)
+		  cases = init cases ++ [{last cases & case_default = kees.case_default}]
+		  [firstCase : otherCases] = [(Case kees, NoPos) \\ kees <- cases]
+		  ((Case {case_guards},_), var_heap, expr_heap, error_admin) =  mergeCases firstCase otherCases var_heap expr_heap error_admin
+		  kees = {kees & case_guards = case_guards}
+		=	(Case kees, var_heap, expr_heap, error_admin)
+		where
+			split_patterns :: CasePatterns -> [CasePatterns]
+			split_patterns (AlgebraicPatterns index patterns)
+				=	[AlgebraicPatterns index [pattern] \\ pattern <- patterns]
+			split_patterns (BasicPatterns basicType patterns)
+				=	[BasicPatterns basicType [pattern] \\ pattern <- patterns]
+			split_patterns (DynamicPatterns patterns)
+				=	[DynamicPatterns [pattern] \\ pattern <- patterns]
+			split_patterns NoPattern
+				=	[NoPattern]
+
+			make_case :: Expression CasePatterns -> Case
+			make_case expr guard
+				=
+				{	case_expr		= expr
+				,	case_guards		= guard
+				,	case_default	= No
+				,	case_ident		= No
+				,	case_info_ptr	= nilPtr
+				,	case_default_pos= NoPos
+				}
+	merge_case expr var_heap expr_heap error_admin
+		=	(expr, var_heap, expr_heap, error_admin)
+			
+
 	build_case NoPattern defaul expr case_ident expr_heap
 		= case defaul of
 			Yes (opt_var, result)