Remove case functions implementation

We're removing this feature as per RFC 51.

Closes #2540.

packages/debug/debug.pony

@@ -25,26 +25,23 @@ primitive Debug
   """
   This is a debug only print utility.
   """
-  fun apply(msg: Stringable, sep: String, stream: DebugStream = DebugOut) =>
-    """
-    If platform is debug configured, print a stringable. The default output
-    stream is stdout.
-    """
-    ifdef debug then
-      _print(msg.string(), stream)
-    end
-
   fun apply(
-    msg: ReadSeq[Stringable],
+    msg: (Stringable | ReadSeq[Stringable]),
     sep: String = ", ",
-    stream: DebugStream)
+    stream: DebugStream = DebugOut)
   =>
     """
-    If platform is debug configured, print a sequence of stringables. The
-    default separator is ", ", and the default output stream is stdout.
+    If platform is debug configured, print either a single stringable or a
+    sequence of stringables. The default separator is ", ", and the default
+    output stream is stdout.
     """
     ifdef debug then
-      _print(sep.join(msg.values()), stream)
+      match msg
+      | let m: Stringable =>
+        _print(m.string(), stream)
+      | let m: ReadSeq[Stringable] =>
+        _print(sep.join(m.values()), stream)
+      end
     end
 
   fun out(msg: Stringable = "") =>

pony.g

@@ -34,7 +34,7 @@ field
   ;
 
 method
-  : ('fun' | 'be' | 'new') ('\\' ID (',' ID)* '\\')? (cap | '@')? ID typeparams? ('(' | LPAREN_NEW) params? ')' (':' type)? '?'? STRING? ('if' rawseq)? ('=>' rawseq)?
+  : ('fun' | 'be' | 'new') ('\\' ID (',' ID)* '\\')? (cap | '@')? ID typeparams? ('(' | LPAREN_NEW) params? ')' (':' type)? '?'? STRING? ('=>' rawseq)?
   ;
 
 annotatedrawseq
@@ -208,8 +208,8 @@ nextatom
   | LPAREN_NEW rawseq tuple? ')'
   | LSQUARE_NEW ('as' type ':')? rawseq? ']'
   | 'object' ('\\' ID (',' ID)* '\\')? cap? ('is' type)? members 'end'
-  | '{' ('\\' ID (',' ID)* '\\')? cap? ID? typeparams? ('(' | LPAREN_NEW) params? ')' lambdacaptures? (':' type)? '?'? '=>' rawseq '}' cap?
-  | '@{' ('\\' ID (',' ID)* '\\')? cap? ID? typeparams? ('(' | LPAREN_NEW) params? ')' lambdacaptures? (':' type)? '?'? '=>' rawseq '}' cap?
+  | '{' ('\\' ID (',' ID)* '\\')? cap? ID? typeparams? ('(' | LPAREN_NEW) lambdaparams? ')' lambdacaptures? (':' type)? '?'? '=>' rawseq '}' cap?
+  | '@{' ('\\' ID (',' ID)* '\\')? cap? ID? typeparams? ('(' | LPAREN_NEW) lambdaparams? ')' lambdacaptures? (':' type)? '?'? '=>' rawseq '}' cap?
   | '@' (ID | STRING) typeargs? ('(' | LPAREN_NEW) positional? named? ')' '?'?
   | '__loc'
   ;
@@ -221,8 +221,8 @@ atom
   | ('(' | LPAREN_NEW) rawseq tuple? ')'
   | ('[' | LSQUARE_NEW) ('as' type ':')? rawseq? ']'
   | 'object' ('\\' ID (',' ID)* '\\')? cap? ('is' type)? members 'end'
-  | '{' ('\\' ID (',' ID)* '\\')? cap? ID? typeparams? ('(' | LPAREN_NEW) params? ')' lambdacaptures? (':' type)? '?'? '=>' rawseq '}' cap?
-  | '@{' ('\\' ID (',' ID)* '\\')? cap? ID? typeparams? ('(' | LPAREN_NEW) params? ')' lambdacaptures? (':' type)? '?'? '=>' rawseq '}' cap?
+  | '{' ('\\' ID (',' ID)* '\\')? cap? ID? typeparams? ('(' | LPAREN_NEW) lambdaparams? ')' lambdacaptures? (':' type)? '?'? '=>' rawseq '}' cap?
+  | '@{' ('\\' ID (',' ID)* '\\')? cap? ID? typeparams? ('(' | LPAREN_NEW) lambdaparams? ')' lambdacaptures? (':' type)? '?'? '=>' rawseq '}' cap?
   | '@' (ID | STRING) typeargs? ('(' | LPAREN_NEW) positional? named? ')' '?'?
   | '__loc'
   ;
@@ -239,6 +239,14 @@ lambdacapture
   : ID (':' type)? ('=' infix)?
   ;
 
+lambdaparams
+  : lambdaparam (',' lambdaparam)*
+  ;
+
+lambdaparam
+  : ID (':' type)? ('=' infix)?
+  ;
+
 positional
   : rawseq (',' rawseq)*
   ;
@@ -340,7 +348,7 @@ literal
   ;
 
 param
-  : parampattern (':' type)? ('=' infix)?
+  : ID ':' type ('=' infix)?
   ;
 
 antlr_0

src/libponyc/ast/parser.c

@@ -73,14 +73,12 @@ DEF(defaultarg);
   RULE("default value", infix);
   DONE();
 
-// postfix [COLON type] [ASSIGN defaultarg]
+// ID [COLON type] [ASSIGN defaultarg]
 DEF(param);
   AST_NODE(TK_PARAM);
-  RULE("name", parampattern);
-  IF(TK_COLON,
-    RULE("parameter type", type);
-    UNWRAP(0, TK_REFERENCE);
-  );
+  TOKEN("parameter name", TK_ID);
+  SKIP("mandatory type declaration on parameter", TK_COLON);
+  RULE("parameter type", type);
   IF(TK_ASSIGN, RULE("default value", defaultarg));
   DONE();
 
@@ -344,6 +342,21 @@ DEF(object);
   SET_CHILD_FLAG(2, AST_FLAG_PRESERVE); // Members
   DONE();
 
+// parampattern [COLON type] [ASSIGN defaultarg]
+DEF(lambdaparam);
+  AST_NODE(TK_PARAM);
+  TOKEN("parameter name", TK_ID);
+  IF(TK_COLON, RULE("parameter type", type));
+  IF(TK_ASSIGN, RULE("default value", defaultarg));
+  DONE();
+
+// lambdaparam {COMMA lambdaparam}
+DEF(lambdaparams);
+  AST_NODE(TK_PARAMS);
+  RULE("parameter", lambdaparam);
+  WHILE(TK_COMMA, RULE("parameter", lambdaparam));
+  DONE();
+
 // ID [COLON type] [ASSIGN infix]
 DEF(lambdacapture);
   AST_NODE(TK_LAMBDACAPTURE);
@@ -362,8 +375,9 @@ DEF(lambdacaptures);
   SKIP(NULL, TK_RPAREN);
   DONE();
 
-// LBRACE [annotations] [CAP] [ID] [typeparams] (LPAREN | LPAREN_NEW) [params]
-// RPAREN [lambdacaptures] [COLON type] [QUESTION] ARROW rawseq RBRACE [CAP]
+// LBRACE [annotations] [CAP] [ID] [typeparams] (LPAREN | LPAREN_NEW)
+// [lambdaparams] RPAREN [lambdacaptures] [COLON type] [QUESTION] ARROW rawseq
+// RBRACE [CAP]
 DEF(lambda);
   PRINT_INLINE();
   AST_NODE(TK_LAMBDA);
@@ -373,7 +387,7 @@ DEF(lambda);
   OPT TOKEN("function name", TK_ID);
   OPT RULE("type parameters", typeparams);
   SKIP(NULL, TK_LPAREN, TK_LPAREN_NEW);
-  OPT RULE("parameters", params);
+  OPT RULE("parameters", lambdaparams);
   SKIP(NULL, TK_RPAREN);
   OPT RULE("captures", lambdacaptures);
   IF(TK_COLON, RULE("return type", type));
@@ -389,8 +403,8 @@ DEF(lambda);
   DONE();
 
 // AT_LBRACE [annotations] [CAP] [ID] [typeparams] (LPAREN | LPAREN_NEW)
-// [params] RPAREN [lambdacaptures] [COLON type] [QUESTION] ARROW rawseq RBRACE
-// [CAP]
+// [lambdaparams] RPAREN [lambdacaptures] [COLON type] [QUESTION] ARROW rawseq
+// RBRACE [CAP]
 DEF(barelambda);
   PRINT_INLINE();
   AST_NODE(TK_BARELAMBDA);
@@ -400,7 +414,7 @@ DEF(barelambda);
   OPT TOKEN("function name", TK_ID);
   OPT RULE("type parameters", typeparams);
   SKIP(NULL, TK_LPAREN, TK_LPAREN_NEW);
-  OPT RULE("parameters", params);
+  OPT RULE("parameters", lambdaparams);
   SKIP(NULL, TK_RPAREN);
   OPT RULE("captures", lambdacaptures);
   IF(TK_COLON, RULE("return type", type));
@@ -1127,11 +1141,10 @@ DEF(method);
   IF(TK_COLON, RULE("return type", type));
   OPT TOKEN(NULL, TK_QUESTION);
   OPT TOKEN(NULL, TK_STRING);
-  IF(TK_IF, RULE("guard expression", rawseq));
   IF(TK_DBLARROW, RULE("method body", rawseq));
   // Order should be:
-  // cap id type_params params return_type error body docstring guard
-  REORDER(0, 1, 2, 3, 4, 5, 8, 6, 7);
+  // cap id type_params params return_type error body docstring
+  REORDER(0, 1, 2, 3, 4, 5, 7, 6);
   DONE();
 
 // (VAR | LET | EMBED) ID [COLON type] [ASSIGN infix]

src/libponyc/ast/treecheckdef.h

@@ -79,8 +79,7 @@ RULE(method,
   CHILD(type, none) // Return type
   CHILD(question, none)
   CHILD(rawseq, none)  // Body
-  CHILD(string, none)
-  CHILD(rawseq, none), // Guard (case methods only)
+  CHILD(string, none),
   TK_FUN, TK_NEW, TK_BE);
 
 RULE(type_params, ONE_OR_MORE(type_param), TK_TYPEPARAMS);
@@ -101,8 +100,8 @@ RULE(params,
 
 RULE(param,
   HAS_TYPE(type)
-  CHILD(id, expr)
-  CHILD(type, none)
+  CHILD(id)
+  CHILD(type)
   CHILD(seq, none),
   TK_PARAM);
 
@@ -378,14 +377,23 @@ RULE(lambda,
   CHILD(cap, none) // Receiver cap
   CHILD(id, none)
   CHILD(type_params, none)
-  CHILD(params, none)
+  CHILD(lambda_params, none)
   CHILD(lambda_captures, none)
   CHILD(type, none) // Return
   CHILD(question, none)
   CHILD(rawseq)
   CHILD(cap, none), // Type reference cap
   TK_LAMBDA);
 
+RULE(lambda_params, ONE_OR_MORE(lambda_param), TK_PARAMS);
+
+RULE(lambda_param,
+  HAS_TYPE(type)
+  CHILD(id)
+  CHILD(type, none)
+  CHILD(seq, none),
+  TK_PARAM);
+
 RULE(lambda_captures, ONE_OR_MORE(lambda_capture), TK_LAMBDACAPTURES);
 
 RULE(lambda_capture,

src/libponyc/expr/lambda.c

@@ -294,16 +294,14 @@ bool expr_lambda(pass_opt_t* opt, ast_t** astp)
         ast_t* param_type = ast_sibling(param_id);
 
         // Convert a "_" parameter to whatever the expected parameter is.
-        if((ast_id(param_id) == TK_REFERENCE) &&
-          is_name_dontcare(ast_name(ast_child(param_id))))
+        if(is_name_dontcare(ast_name(param_id)))
         {
           ast_replace(&param_id, ast_child(def_param));
           ast_replace(&param_type, ast_childidx(def_param, 1));
         }
         // Give a type-unspecified parameter the type of the expected parameter.
         else if(ast_id(param_type) == TK_NONE)
         {
-          ast_replace(&param_id, ast_child(param_id)); // unwrap reference's id
           ast_replace(&param_type, ast_childidx(def_param, 1));
         }
 
@@ -394,8 +392,7 @@ bool expr_lambda(pass_opt_t* opt, ast_t** astp)
       TREE(ret_type)
       TREE(raises)
       TREE(body)
-      NONE    // Doc string
-      NONE)); // Guard
+      NONE)); // Doc string
 
   ast_list_append(members, &last_member, apply);
   ast_setflag(members, AST_FLAG_PRESERVE);
@@ -693,7 +690,6 @@ bool expr_object(pass_opt_t* opt, ast_t** astp)
       NONE
       NODE(TK_SEQ,
         NODE(TK_TRUE))
-      NONE
       NONE));
 
   BUILD(type_ref, ast, NODE(TK_REFERENCE, ID(c_id)));