Add bare methods and bare lambdas (RFC 34)

These new language constructs can be used in FFI interoperation with C
libraries that use function pointers as callbacks.

Closes #1690.

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? ('if' rawseq)? ('=>' rawseq)?
   ;
 
 annotatedrawseq
@@ -202,6 +202,7 @@ nextatom
   | 'object' ('\\' ID (',' ID)* '\\')? cap? ('is' type)? members 'end'
   | '{' ('\\' ID (',' ID)* '\\')? cap? ID? typeparams? ('(' | LPAREN_NEW) params? ')' lambdacaptures? (':' type)? '?'? '=>' rawseq '}' cap?
   | 'lambda' ('\\' ID (',' ID)* '\\')? cap? ID? typeparams? ('(' | LPAREN_NEW) params? ')' lambdacaptures? (':' type)? '?'? '=>' rawseq 'end'
+  | '@{' ('\\' ID (',' ID)* '\\')? cap? ID? typeparams? ('(' | LPAREN_NEW) params? ')' lambdacaptures? (':' type)? '?'? '=>' rawseq '}' cap?
   | '@' (ID | STRING) typeargs? ('(' | LPAREN_NEW) positional? named? ')' '?'?
   | '__loc'
   ;
@@ -215,6 +216,7 @@ atom
   | 'object' ('\\' ID (',' ID)* '\\')? cap? ('is' type)? members 'end'
   | '{' ('\\' ID (',' ID)* '\\')? cap? ID? typeparams? ('(' | LPAREN_NEW) params? ')' lambdacaptures? (':' type)? '?'? '=>' rawseq '}' cap?
   | 'lambda' ('\\' ID (',' ID)* '\\')? cap? ID? typeparams? ('(' | LPAREN_NEW) params? ')' lambdacaptures? (':' type)? '?'? '=>' rawseq 'end'
+  | '@{' ('\\' ID (',' ID)* '\\')? cap? ID? typeparams? ('(' | LPAREN_NEW) params? ')' lambdacaptures? (':' type)? '?'? '=>' rawseq '}' cap?
   | '@' (ID | STRING) typeargs? ('(' | LPAREN_NEW) positional? named? ')' '?'?
   | '__loc'
   ;
@@ -253,6 +255,11 @@ atomtype
   | ('(' | LPAREN_NEW) infixtype tupletype? ')'
   | nominal
   | lambdatype
+  | barelambdatype
+  ;
+
+barelambdatype
+  : '@{' cap? ID? typeparams? ('(' | LPAREN_NEW) (type (',' type)*)? ')' (':' type)? '?'? '}' (cap | gencap)? ('^' | '!')?
   ;
 
 lambdatype

src/libponyc/ast/ast.c

@@ -40,7 +40,7 @@
  * no annotation, the type will be stored in the annotation_type field.
  *
  * These situations can be distinguished because an annotation must always be a
- * TK_BACKSLASH, and the type may never be a TK_BACKSLASH.
+ * TK_ANNOTATION, and the type may never be a TK_ANNOTATION.
  *
  * It is STRONGLY recommended to only access them through provided functions:
  *   ast_type()
@@ -653,13 +653,13 @@ ast_t* ast_type(ast_t* ast)
   pony_assert(ast != NULL);
 
   // An annotation may never have a type.
-  if(ast_id(ast) == TK_BACKSLASH)
+  if(ast_id(ast) == TK_ANNOTATION)
     return NULL;
 
   // If the annotation_type is an annotation, the type node (if any) is in the
   // annotation_type field of the annotation node.
   ast_t* type = ast->annotation_type;
-  if((type != NULL) && (ast_id(type) == TK_BACKSLASH))
+  if((type != NULL) && (ast_id(type) == TK_ANNOTATION))
     type = type->annotation_type;
 
   return type;
@@ -670,12 +670,12 @@ static void settype(ast_t* ast, ast_t* type, bool allow_free)
   pony_assert(ast != NULL);
 
   // An annotation may never have a type.
-  if(ast_id(ast) == TK_BACKSLASH)
+  if(ast_id(ast) == TK_ANNOTATION)
     pony_assert(type == NULL);
 
-  // A type can never be a TK_BACKSLASH (the annotation token).
+  // A type can never be a TK_ANNOTATION.
   if(type != NULL)
-    pony_assert(ast_id(type) != TK_BACKSLASH);
+    pony_assert(ast_id(type) != TK_ANNOTATION);
 
   ast_t* prev_type = ast_type(ast);
   if(prev_type == type)
@@ -690,7 +690,7 @@ static void settype(ast_t* ast, ast_t* type, bool allow_free)
   }
 
   if((ast->annotation_type != NULL) &&
-    (ast_id(ast->annotation_type) == TK_BACKSLASH))
+    (ast_id(ast->annotation_type) == TK_ANNOTATION))
     ast->annotation_type->annotation_type = type;
   else
     ast->annotation_type = type;
@@ -709,12 +709,12 @@ ast_t* ast_annotation(ast_t* ast)
   pony_assert(ast != NULL);
 
   // An annotation may never be annotated.
-  if(ast_id(ast) == TK_BACKSLASH)
+  if(ast_id(ast) == TK_ANNOTATION)
     return NULL;
 
   // If annotation_type is an annotation, we return it.
   ast_t* annotation = ast->annotation_type;
-  if((annotation != NULL) && (ast_id(annotation) == TK_BACKSLASH))
+  if((annotation != NULL) && (ast_id(annotation) == TK_ANNOTATION))
     return annotation;
 
   return NULL;
@@ -725,12 +725,12 @@ void setannotation(ast_t* ast, ast_t* annotation, bool allow_free)
   pony_assert(ast != NULL);
 
   // An annotation may never be annotated.
-  if(ast_id(ast) == TK_BACKSLASH)
+  if(ast_id(ast) == TK_ANNOTATION)
     pony_assert(annotation == NULL);
 
-  // An annotation must always be a TK_BACKSLASH (or NULL).
+  // An annotation must always be a TK_ANNOTATION (or NULL).
   if(annotation != NULL)
-    pony_assert(ast_id(annotation) == TK_BACKSLASH);
+    pony_assert(ast_id(annotation) == TK_ANNOTATION);
 
   ast_t* prev_annotation = ast_annotation(ast);
   if(prev_annotation == annotation)
@@ -781,7 +781,7 @@ bool ast_has_annotation(ast_t* ast, const char* name)
 
   ast_t* annotation = ast_annotation(ast);
 
-  if((annotation != NULL) && (ast_id(annotation) == TK_BACKSLASH))
+  if((annotation != NULL) && (ast_id(annotation) == TK_ANNOTATION))
   {
     const char* strtab_name = stringtab(name);
     ast_t* elem = ast_child(annotation);

src/libponyc/ast/astbuild.h

@@ -29,6 +29,10 @@
  */
 #define BUILD(var, existing, ...) \
   ast_t* var; \
+  BUILD_NO_DECL(var, existing, __VA_ARGS__)
+
+/// Builds an AST but without declaring a new variable.
+#define BUILD_NO_DECL(var, existing, ...) \
   { \
     ast_t* basis_ast = existing; \
     ast_t* parent = NULL; \

src/libponyc/ast/lexer.c

@@ -84,6 +84,8 @@ static const lextoken_t symbols[] =
 
   { "\\", TK_BACKSLASH },
 
+  { "@{", TK_AT_LBRACE },
+
   { "{", TK_LBRACE },
   { "}", TK_RBRACE },
   { "(", TK_LPAREN },
@@ -244,6 +246,7 @@ static const lextoken_t abstract[] =
   { "thistype", TK_THISTYPE },
   { "funtype", TK_FUNTYPE },
   { "lambdatype", TK_LAMBDATYPE },
+  { "barelambdatype", TK_BARELAMBDATYPE },
   { "dontcaretype", TK_DONTCARETYPE },
   { "infer", TK_INFERTYPE },
   { "errortype", TK_ERRORTYPE },
@@ -266,6 +269,8 @@ static const lextoken_t abstract[] =
   { "lambdacaptures", TK_LAMBDACAPTURES },
   { "lambdacapture", TK_LAMBDACAPTURE },
 
+  { "barelambda", TK_BARELAMBDA },
+
   { "seq", TK_SEQ },
   { "qualify", TK_QUALIFY },
   { "call", TK_CALL },
@@ -297,6 +302,8 @@ static const lextoken_t abstract[] =
   { "bechain", TK_BECHAIN },
   { "funchain", TK_FUNCHAIN },
 
+  { "annotation", TK_ANNOTATION },
+
   { "\\n", TK_NEWLINE },
   {NULL, (token_id)0}
 };

src/libponyc/ast/parser.c

@@ -149,12 +149,17 @@ DEF(cap);
   TOKEN("capability", TK_ISO, TK_TRN, TK_REF, TK_VAL, TK_BOX, TK_TAG);
   DONE();
 
-  // GENCAP
+// GENCAP
 DEF(gencap);
   TOKEN("generic capability", TK_CAP_READ, TK_CAP_SEND, TK_CAP_SHARE,
     TK_CAP_ALIAS, TK_CAP_ANY);
   DONE();
 
+// AT
+DEF(bare);
+  TOKEN("@", TK_AT);
+  DONE();
+
 // ID [DOT ID] [typeargs] [CAP] [EPHEMERAL | ALIASED]
 DEF(nominal);
   AST_NODE(TK_NOMINAL);
@@ -242,9 +247,27 @@ DEF(lambdatype);
   OPT TOKEN(NULL, TK_EPHEMERAL, TK_ALIASED);
   DONE();
 
-// (thistype | cap | typeexpr | nominal | lambdatype)
+// AT_LBRACE [CAP] [ID] [typeparams] (LPAREN | LPAREN_NEW) [typelist] RPAREN
+// [COLON type] [QUESTION] RBRACE [CAP] [EPHEMERAL | ALIASED]
+DEF(barelambdatype);
+  AST_NODE(TK_BARELAMBDATYPE);
+  SKIP(NULL, TK_AT_LBRACE);
+  OPT RULE("capability", cap);
+  OPT TOKEN("function name", TK_ID);
+  OPT RULE("type parameters", typeparams);
+  SKIP(NULL, TK_LPAREN, TK_LPAREN_NEW);
+  OPT RULE("parameters", typelist);
+  SKIP(NULL, TK_RPAREN);
+  IF(TK_COLON, RULE("return type", type));
+  OPT TOKEN(NULL, TK_QUESTION);
+  SKIP(NULL, TK_RBRACE);
+  OPT RULE("capability", cap, gencap);
+  OPT TOKEN(NULL, TK_EPHEMERAL, TK_ALIASED);
+  DONE();
+
+// (thistype | cap | typeexpr | nominal | lambdatype | barelambdatype)
 DEF(atomtype);
-  RULE("type", thistype, cap, groupedtype, nominal, lambdatype);
+  RULE("type", thistype, cap, groupedtype, nominal, lambdatype, barelambdatype);
   DONE();
 
 // ARROW type
@@ -292,6 +315,7 @@ DEF(positional);
 DEF(annotations);
   PRINT_INLINE();
   TOKEN(NULL, TK_BACKSLASH);
+  MAP_ID(TK_BACKSLASH, TK_ANNOTATION);
   TOKEN("annotation", TK_ID);
   WHILE(TK_COMMA, TOKEN("annotation", TK_ID));
   TERMINATE("annotations", TK_BACKSLASH);
@@ -380,6 +404,33 @@ DEF(lambda);
   SET_CHILD_FLAG(7, AST_FLAG_PRESERVE); // Body
   DONE();
 
+// AT_LBRACE [annotations] [CAP] [ID] [typeparams] (LPAREN | LPAREN_NEW)
+// [params] RPAREN [lambdacaptures] [COLON type] [QUESTION] ARROW rawseq RBRACE
+// [CAP]
+DEF(barelambda);
+  PRINT_INLINE();
+  AST_NODE(TK_BARELAMBDA);
+  SKIP(NULL, TK_AT_LBRACE);
+  ANNOTATE(annotations);
+  OPT RULE("receiver capability", cap);
+  OPT TOKEN("function name", TK_ID);
+  OPT RULE("type parameters", typeparams);
+  SKIP(NULL, TK_LPAREN, TK_LPAREN_NEW);
+  OPT RULE("parameters", params);
+  SKIP(NULL, TK_RPAREN);
+  OPT RULE("captures", lambdacaptures);
+  IF(TK_COLON, RULE("return type", type));
+  OPT TOKEN(NULL, TK_QUESTION);
+  SKIP(NULL, TK_DBLARROW);
+  RULE("lambda body", rawseq);
+  TERMINATE("lambda expression", TK_RBRACE);
+  OPT RULE("reference capability", cap);
+  SET_CHILD_FLAG(2, AST_FLAG_PRESERVE); // Type parameters
+  SET_CHILD_FLAG(3, AST_FLAG_PRESERVE); // Parameters
+  SET_CHILD_FLAG(5, AST_FLAG_PRESERVE); // Return type
+  SET_CHILD_FLAG(7, AST_FLAG_PRESERVE); // Body
+  DONE();
+
 // AS type ':'
 DEF(arraytype);
   PRINT_INLINE();
@@ -470,16 +521,18 @@ DEF(ffi);
   OPT TOKEN(NULL, TK_QUESTION);
   DONE();
 
-// ref | this | literal | tuple | array | object | lambda | ffi | location
+// ref | this | literal | tuple | array | object | lambda | barelambda | ffi |
+// location
 DEF(atom);
   RULE("value", ref, thisliteral, literal, groupedexpr, array, object, lambda,
-    oldlambda, ffi, location);
+    oldlambda, barelambda, ffi, location);
   DONE();
 
-// ref | this | literal | tuple | array | object | lambda | ffi | location
+// ref | this | literal | tuple | array | object | lambda | barelambda| ffi |
+// location
 DEF(nextatom);
   RULE("value", ref, thisliteral, literal, nextgroupedexpr, nextarray, object,
-    lambda, oldlambda, ffi, location);
+    lambda, oldlambda, barelambda, ffi, location);
   DONE();
 
 // DOT ID
@@ -1061,13 +1114,13 @@ DEF(annotatedseq);
   SCOPE();
   DONE();
 
-// (FUN | BE | NEW) [annotations] [CAP] ID [typeparams] (LPAREN | LPAREN_NEW)
-// [params] RPAREN [COLON type] [QUESTION] [ARROW rawseq]
+// (FUN | BE | NEW) [annotations] [CAP | AT] ID [typeparams]
+// (LPAREN | LPAREN_NEW) [params] RPAREN [COLON type] [QUESTION] [ARROW rawseq]
 DEF(method);
   TOKEN(NULL, TK_FUN, TK_BE, TK_NEW);
   ANNOTATE(annotations);
   SCOPE();
-  OPT RULE("capability", cap);
+  OPT RULE("capability", cap, bare);
   TOKEN("method name", TK_ID);
   OPT RULE("type parameters", typeparams);
   SKIP(NULL, TK_LPAREN, TK_LPAREN_NEW);

src/libponyc/ast/token.h

@@ -58,6 +58,7 @@ typedef enum token_id
   TK_MOD,
   TK_MOD_TILDE,
   TK_AT,
+  TK_AT_LBRACE,
 
   TK_LSHIFT,
   TK_LSHIFT_TILDE,
@@ -109,6 +110,7 @@ typedef enum token_id
   TK_ACTOR,
   TK_OBJECT,
   TK_LAMBDA,
+  TK_BARELAMBDA,
 
   TK_AS,
   TK_IS,
@@ -196,6 +198,7 @@ typedef enum token_id
   TK_THISTYPE,
   TK_FUNTYPE,
   TK_LAMBDATYPE,
+  TK_BARELAMBDATYPE,
   TK_DONTCARETYPE,
   TK_INFERTYPE,
   TK_ERRORTYPE,
@@ -250,6 +253,8 @@ typedef enum token_id
   TK_BECHAIN,
   TK_FUNCHAIN,
 
+  TK_ANNOTATION,
+
   // Pseudo tokens that never actually exist
   TK_NEWLINE,  // Used by parser macros
   TK_FLATTEN,  // Used by parser macros for tree building

src/libponyc/codegen/codegen.c

@@ -1103,12 +1103,13 @@ LLVMValueRef codegen_addfun(compile_t* c, const char* name, LLVMTypeRef type)
 }
 
 void codegen_startfun(compile_t* c, LLVMValueRef fun, LLVMMetadataRef file,
-  LLVMMetadataRef scope)
+  LLVMMetadataRef scope, bool bare)
 {
   compile_frame_t* frame = push_frame(c);
 
   frame->fun = fun;
   frame->is_function = true;
+  frame->bare_function = bare;
   frame->di_file = file;
   frame->di_scope = scope;
 
@@ -1131,6 +1132,7 @@ void codegen_pushscope(compile_t* c, ast_t* ast)
   compile_frame_t* frame = push_frame(c);
 
   frame->fun = frame->prev->fun;
+  frame->bare_function = frame->prev->bare_function;
   frame->break_target = frame->prev->break_target;
   frame->break_novalue_target = frame->prev->break_novalue_target;
   frame->continue_target = frame->prev->continue_target;
@@ -1235,6 +1237,7 @@ void codegen_pushloop(compile_t* c, LLVMBasicBlockRef continue_target,
   compile_frame_t* frame = push_frame(c);
 
   frame->fun = frame->prev->fun;
+  frame->bare_function = frame->prev->bare_function;
   frame->break_target = break_target;
   frame->break_novalue_target = break_novalue_target;
   frame->continue_target = continue_target;
@@ -1253,6 +1256,7 @@ void codegen_pushtry(compile_t* c, LLVMBasicBlockRef invoke_target)
   compile_frame_t* frame = push_frame(c);
 
   frame->fun = frame->prev->fun;
+  frame->bare_function = frame->prev->bare_function;
   frame->break_target = frame->prev->break_target;
   frame->break_novalue_target = frame->prev->break_novalue_target;
   frame->continue_target = frame->prev->continue_target;
@@ -1357,10 +1361,13 @@ LLVMBasicBlockRef codegen_block(compile_t* c, const char* name)
 }
 
 LLVMValueRef codegen_call(compile_t* c, LLVMValueRef fun, LLVMValueRef* args,
-  size_t count)
+  size_t count, bool setcc)
 {
   LLVMValueRef result = LLVMBuildCall(c->builder, fun, args, (int)count, "");
-  LLVMSetInstructionCallConv(result, c->callconv);
+
+  if(setcc)
+    LLVMSetInstructionCallConv(result, c->callconv);
+
   return result;
 }