implement compound and designated literals support

Lambdas rotted because there wasn't any test for them, and after
return type moved to the end, lambdas stayed assumning it in the
front. We fix this and add test program

.gitea/workflows/build.yaml

@@ -57,7 +57,9 @@ jobs:
           hash -r
           csc -version
 
-      # Eggs are pinned in eggs.lock and installed by the Makefile into .eggs/.
+      - name: Install dependencies
+        run: make deps
+
       - name: Build sexc
         run: make && ./sexc --help
 

Makefile

@@ -34,24 +34,27 @@ DEPSLOCK = eggs.lock
 EGGS_DIR := $(abspath .eggs)
 
 # Compiler's own repository (types.db, chicken.*), ignoring ambient venv vars.
-SYSTEM_CHICKEN_REPO := $(shell env -u CHICKEN_INSTALL_REPOSITORY -u CHICKEN_REPOSITORY_PATH -u CHICKEN_EGG_CACHE -u CHICKEN_INSTALL_PREFIX $(CHICKEN_INSTALL) -repository 2>/dev/null)
+SYSTEM_CHICKEN_REPO := $(shell env \
+	-u CHICKEN_INSTALL_REPOSITORY -u CHICKEN_REPOSITORY_PATH \
+	-u CHICKEN_EGG_CACHE -u CHICKEN_INSTALL_PREFIX \
+	$(CHICKEN_INSTALL) -repository 2>/dev/null)
 CHICKEN_ABI := $(notdir $(SYSTEM_CHICKEN_REPO))
 EGGS_STAMP := $(EGGS_DIR)/.installed-$(CHICKEN_ABI)
 
-export CHICKEN_EGG_CACHE := $(EGGS_DIR)/cache
-export CHICKEN_INSTALL_REPOSITORY := $(EGGS_DIR)
-export CHICKEN_INSTALL_PREFIX := $(EGGS_DIR)
+# Try project-local chicken repository first. In case it doesn't exist (packaging for distros),
+# system-wide repository will be used.
+unexport CHICKEN_INSTALL_REPOSITORY
+unexport CHICKEN_EGG_CACHE
+unexport CHICKEN_INSTALL_PREFIX
 export CHICKEN_REPOSITORY_PATH := $(EGGS_DIR):$(SYSTEM_CHICKEN_REPO)
 
 all: sexc
 
-sexc: $(EGGS_STAMP) $(OBJ) main.scm
+sexc: $(OBJ) main.scm
 	$(CHICKEN_C) $(CSC_FLAGS) main.scm -o sexc-tmp -link sexc
         # otherwise csc hangs, probably because it tries to compile to sexc.o first
 	mv sexc-tmp sexc
 
-$(OBJ): $(EGGS_STAMP)
-
 #------------------------------------------------------------------
 
 utils.o: utils.module.scm utils.scm
@@ -82,16 +85,16 @@ sexc.o: sexc.module.scm types.o sexc.scm fmt-c-writer.o sex-macros.o sex-modules
 	$(CHICKEN_C) $(CSC_FLAGS) $(MODULE_FLAGS) sexc.module.scm -o sexc.o -unit sexc -link fmt-c-writer,sex-macros,sex-modules,reader,semen,types,utils
 
 # Unit testing
-sex-tests: $(EGGS_STAMP)
+sex-tests:
 	$(MAKE) -C ./tests sex-tests
 	cp ./tests/sex-tests ./
 
-sextest: $(EGGS_STAMP)
+sextest:
 	$(MAKE) -C ./tools/sextest sextest
 	cp ./tools/sextest/sextest .
 
 SEX_TEST_PROGRAMS = hello-world lists comments unicode serialize features \
-                    feature-flags
+                    feature-flags lambdas compound-literals
 
 # Multi-module linking is checked end to end; see tests/modules/Makefile.
 check-modules: sexc
@@ -116,9 +119,11 @@ installdirs:
 uninstall:
 	rm -f $(DESTDIR)$(bindir)/sexc
 
-# eggs.lock is the pin file (chicken-status -list). Install from it;
-# do not float versions on a normal build. Regenerating the lock:
-#   make deps-update
+$(EGGS_STAMP) deps-update: export CHICKEN_EGG_CACHE := $(EGGS_DIR)/cache
+$(EGGS_STAMP) deps-update: export CHICKEN_INSTALL_REPOSITORY := $(EGGS_DIR)
+$(EGGS_STAMP) deps-update: export CHICKEN_INSTALL_PREFIX := $(EGGS_DIR)
+$(EGGS_STAMP) deps-update: export CHICKEN_REPOSITORY_PATH := $(EGGS_DIR):$(SYSTEM_CHICKEN_REPO)
+
 $(EGGS_STAMP): $(DEPSLOCK)
 	mkdir -p $(CHICKEN_EGG_CACHE)
 	$(CHICKEN_INSTALL) -force -from-list $(DEPSLOCK)
@@ -126,10 +131,10 @@ $(EGGS_STAMP): $(DEPSLOCK)
 
 deps: $(EGGS_STAMP)
 
-deps-update: $(DEPSFILE)
-	rm -rf $(EGGS_DIR)
+deps-update: $(DEPSFILE) deps-clean
 	mkdir -p $(CHICKEN_EGG_CACHE)
 	$(CHICKEN_INSTALL) -force $$(cat $(DEPSFILE))
+	# Local repo only: a system path here would leak distro eggs into the lock.
 	CHICKEN_REPOSITORY_PATH=$(EGGS_DIR) $(CHICKEN_STATUS) -list | sort > $(DEPSLOCK).tmp
 	mv $(DEPSLOCK).tmp $(DEPSLOCK)
 	touch $(EGGS_STAMP)

Readme.org

@@ -12,22 +12,25 @@ Sex is statically typed, compiled general purpose language.
 First, get yourself a Chicken, then, some Chicken deps. You also will
 need a C compiler.
 
-Eggs are installed into a project-local ~.eggs/~ repository; they do not
-touch the Chicken system repository.
-
-** Compilation
+** Development
 #+begin_src sh
+  make deps
   make
 #+end_src
 
-That installs pinned eggs from ~eggs.lock~ into ~.eggs/~ if needed, then
-builds ~sexc~. ~dependencies.txt~ is the unpinned request list. To
-refresh ~eggs.lock~ after changing it:
+~make deps~ installs pinned eggs from ~eggs.lock~ into a project-local
+~.eggs/~ repository. ~dependencies.txt~ is the unpinned request list.
+To refresh ~eggs.lock~ after changing it:
 
 #+begin_src sh
   make deps-update
 #+end_src
 
+** Packaging for system package managers
+- Depend ~sex~ package on Chicken-6 (with ~libchicken.a~) and all eggs from ~dependencies.txt~.
+- Compile and install with ~make~ (usually no other arguments required).
+- Move resulting ~sexc~ binary to the appropriate place.
+
 ** Static compilation
 The default ~CSC_FLAGS~ include ~-static~, so ~sexc~ does not need
 ~.eggs~ at runtime and ~make install~ stays relocatable. Chicken must
@@ -172,6 +175,38 @@ e.g. for checking output for other platform:
 sexc example/sdl3-triangle.sex -C --no-platform-features --features=linux,unix,x86-64
 #+end_src
 
+** Aggregate initializers and compound literals
+~#(...)~ is a brace initializer. On its own it has no type and takes one
+from where it is written:
+
+#+begin_src scheme
+(var p (struct point) #(1 2))
+#+end_src
+
+A ~:~ inside one ends a type and makes the whole thing a compound
+literal --- an unnamed object of that type, usable anywhere an
+expression is:
+
+#+begin_src scheme
+(var q (struct point) #(struct point : 3 4))
+(var a (* int) #([int 3] : 10 20 30))
+(draw-line ui #(struct point : 0 0) end)
+(var p (* struct point) (& #(struct point : 9 9)))  ; an lvalue, so `&' works
+#+end_src
+
+The type is written as bare words, the way it is everywhere else in the
+language; ~:~ is what ends it.
+
+A leading ~.~ names a field, so initializers may be designated, given in
+any order, and mixed with positional ones:
+
+#+begin_src scheme
+(var r (struct named) #(struct named : .n 7 .first-name "zoe"))
+#+end_src
+
+A compound literal written inside a block lives until the end of that
+block and no longer, so returning its address is a dangling pointer.
+
 ** Syntactic macros
 Sex has support for syntactic macros. Macro definitions look like
 functions: they have a name, an argument list and a body. Macro should

example/lambdas.sex

@@ -6,14 +6,14 @@
 (pub fn main () int
   (var a int 10)
   (var b int 20)
-  (var (fn ((int) (int)) int) sum-fn sum)
+  (var sum-fn (fn ((int) (int)) int) sum)
 
-  (var (fn ((int) (int)) int) sum-lambda
+  (var sum-lambda (fn ((int) (int)) int)
 
        (lambda ((a int) (b int)) int ()
          (return (+ a b))))
 
-  (var (fn ((int)) int) sum-lambda-2
+  (var sum-lambda-2 (fn ((int)) int)
 
        (lambda ((a int)) int ()
          (return (+ a 20))))
@@ -28,9 +28,9 @@
                                             (return (+ a b 100)))
                                           a b))
 
-  (var (fn ((int)) int) l-1
+  (var l-1 (fn ((int)) int)
        (lambda ((a int)) int ()
-         (var (fn ((int)) int) l-2
+         (var l-2 (fn ((int)) int)
               (lambda ((a int)) int ()
                 (return (+ 60 a))))
          (return (+ 600 (l-2 a)))))

fmt-c-writer.scm

@@ -120,10 +120,6 @@ forms, and what remains."
     ((|\||) 'bit-or)
     ((|\|\||) '%or)
     ((|\|=|) 'bit-or=)
-    ;; uh things we do for c89 compatibility
-    ((bool) 'int)
-    ((true) 1)
-    ((false) 0)
     (else
      (if (symbol? atom)
          (unkebabify atom)
@@ -176,9 +172,7 @@ forms, and what remains."
 
 (define (walk-expr form)
   (match form
-    ((? vector?)
-     (list->vector
-      (walk-expr (vector->list form))))
+    ((? vector?) (walk-initializer (vector->list form)))
     ((? atom?)
      (atom-to-fmt-c form))
     ;; (comment "text") -> /* text */. `%comment' is the fmt-c directive.
@@ -238,6 +232,48 @@ forms, and what remains."
     ;; Drop comments so they will not generate additional comma
     (else (map walk-expr (remove comment-form? form)))))
 
+;;; #(a b c) is a brace initializer. A `:' inside one ends a type and
+;;; turns the whole thing into a C99 compound literal:
+;;; #(struct point : 1 2) is (struct point){1, 2}, and the type is
+;;; written as bare words, the way it is everywhere else in the
+;;; language. `:' is the separator because it is the one thing that can
+;;; be neither a type word nor an expression -- a named form would be a
+;;; C identifier, and so shadowable (see issue #36).
+(define (walk-initializer elements)
+  (let ((parts (list-split (remove comment-form? elements) ':)))
+    (if (null? (cdr parts))
+        (list->vector (walk-designators (car parts)))
+        (cons* '%compound
+               (walk-type (maybe-unwrap-type (car parts)))
+               (walk-designators (cadr parts))))))
+
+;;; `.field value' is a designated initializer; anything else is
+;;; positional. C lets the two be mixed, and nothing here stops it. A
+;;; leading `.' cannot begin a C identifier, so a field name needs no
+;;; keyword to introduce it and cannot collide with one.
+(define (walk-designators elements)
+  (let loop ((es elements) (acc (list)))
+    (match es
+      (() (reverse acc))
+      (((? designator? d))
+       (sex-error elements "designated initializer without a value" d))
+      (((? designator? d) value . rest)
+       (loop rest
+             (cons (list '%designate
+                         (atom-to-fmt-c (designator-field d))
+                         (walk-expr value))
+                   acc)))
+      ((e . rest) (loop rest (cons (walk-expr e) acc))))))
+
+(define (designator? x)
+  (and (symbol? x)
+       (let ((s (symbol->string x)))
+         (and (> (string-length s) 1)
+              (char=? #\. (string-ref s 0))))))
+
+(define (designator-field d)
+  (string->symbol (substring (symbol->string d) 1)))
+
 (define (walk-var form)
   ;; (var a int) -> (%var int a)
   ;; (var a (const int) 32) -> (%var (const int) a 32)
@@ -380,8 +416,8 @@ forms, and what remains."
   (map arg-type (remove comment-form? form)))
 
 (define (walk-function form)
-  ;; (fn ret-type name arglist body) -> normal function
-  ;; (fn ret-type name arglist) -> prototype
+  ;; (fn name arglist ret-type body) -> normal function
+  ;; (fn name arglist ret-type) -> prototype
   (if (>= (length form) 5)
       (walk-fn-def form)
       (cons '%prototype (cdr (walk-fn-def form)))))

semen.scm

@@ -72,7 +72,7 @@
     ((or ('var . _)
          ('pub 'var . _)
          ('extern 'var . _)) (process-global-var sex-form acc))
-    (('include _) (cons sex-form acc))
+    (('include . includes) (process-includes sex-form includes acc))
     ((or ('define name . _)
          ('pub 'define name . _))
      (add-define name sex-form)
@@ -92,6 +92,17 @@
 
     (else (sex-error sex-form "unknown top level form" sex-form))))
 
+(define (process-includes sex-form includes acc)
+  ;; consume (include ...) form and add to acc
+  ;; (include <inc>) for each include
+  (let process ((includes includes)
+                (acc acc))
+    (if (null? includes)
+        acc
+        (process (cdr includes)
+                 (cons (copy-form-source! sex-form `(include ,(car includes)))
+                       acc)))))
+
 (define (process-imports module-public-forms acc)
   ;; consume (import ...) form and process imports so
   ;; data types end up in types db
@@ -140,28 +151,91 @@
   (cons (copy-form-source! form `(typedef ,target ,new-type)) acc))
 
 ;;; Fn processing
+;;;
+;;; A string as the first body form is a docstring. In the generated
+;;; C code it will be placed as a C commentary just before the function
+;;; definition (actually that works for all blocky things: enum, struct, union as well).
+
+(define (fn-header-length fn-form)
+  (if (memq (first fn-form) '(pub extern)) 5 4))
+
+(define (fn-core form)
+  ;; The (fn name args rettype . body) list, without pub/extern
+  (if (memq (first form) '(pub extern))
+      (cdr form)
+      form))
+
+(define (take-leading-docstring forms)
+  ;; If FORMS starts with a string, possibly after comment forms, return
+  ;; that string and FORMS without it. Otherwise #f and FORMS unchanged
+  (let loop ((fs forms) (prefix (list)))
+    (match fs
+      (() (values #f forms))
+      (((and cmt ('comment . _)) . rest)
+       (loop rest (cons cmt prefix)))
+      (((? string? doc) . rest)
+       (values doc (append (reverse prefix) rest)))
+      (_ (values #f forms)))))
+
+(define (extract-fn-docstring fn-form)
+  (let ((lift
+         (lambda (proto body)
+           (let-values (((doc rest) (take-leading-docstring body)))
+             (if doc
+                 (values doc (copy-form-source! fn-form (append proto rest)))
+                 (values #f fn-form))))))
+    (match fn-form
+      (('pub 'fn name args ret . body)
+       (lift `(pub fn ,name ,args ,ret) body))
+      (('extern 'fn name args ret . body)
+       (lift `(extern fn ,name ,args ,ret) body))
+      (('fn name args ret . body)
+       (lift `(fn ,name ,args ,ret) body))
+      (_ (values #f fn-form)))))
+
+(define (extract-aggregate-docstring form)
+  ;; A string immediately after the name is the docstring; comments
+  ;; between name and fields are not skipped, they already confuse the
+  ;; writer
+  (match form
+    (('pub (and kind (or 'struct 'union 'enum))
+           (? symbol? name) (? string? doc) . rest)
+     (values doc (copy-form-source! form `(pub ,kind ,name ,@rest))))
+    (((and kind (or 'struct 'union 'enum))
+      (? symbol? name) (? string? doc) . rest)
+     (values doc (copy-form-source! form `(,kind ,name ,@rest))))
+    (_ (values #f form))))
+
+(define (with-docstring doc form acc)
+  ;; acc is newest-first; FORM is consed last so the final reverse
+  ;; emits the comment immediately before the declaration
+  (cons form
+        (if doc
+            (cons (list 'comment doc) acc)
+            acc)))
 
 (define (strip-fn-header-comments fn-form)
-  ;; ([pub|extern] fn name arglist rettype)
-  (strip-header-comments fn-form
-                         (if (memq (car fn-form) '(pub extern)) 5 4)))
+  ;; ([pub|extern] fn name arglist rettype). Comments in the body are
+  ;; left in place as ordinary statements and preserved into the
+  ;; generated C.
+  (strip-header-comments fn-form (fn-header-length fn-form)))
 
 (define (process-fn sex-fn-raw acc)
-  (let* ((sex-fn (strip-fn-header-comments sex-fn-raw))
-         (expanded (macro-expand sex-fn))
-         (env (make-hash-table))
-         (processed
-          (walk-form
-           expanded
-           fn-walker
-           (begin
-             (set! (hash-table-ref env :fn-name) (sex-fn-name expanded))
-             (set! (hash-table-ref env :lambda-counter) 0)
-             (set! (hash-table-ref env :lambda-aux-code) (list))
-             env))))
-
-    (cons processed
-          (append (hash-table-ref env :lambda-aux-code) acc))))
+  (let-values (((doc sex-fn)
+                (extract-fn-docstring (strip-fn-header-comments sex-fn-raw))))
+    (let* ((expanded (macro-expand sex-fn))
+           (env (make-hash-table))
+           (processed
+            (walk-form
+             expanded
+             fn-walker
+             (begin
+               (set! (hash-table-ref env :fn-name) (sex-fn-name expanded))
+               (set! (hash-table-ref env :lambda-counter) 0)
+               (set! (hash-table-ref env :lambda-aux-code) (list))
+               env))))
+      (with-docstring doc processed
+                      (append (hash-table-ref env :lambda-aux-code) acc)))))
 
 (define (fn-walker form env)
   (if (eq? 'lambda (car form))
@@ -181,10 +255,10 @@
 
 (define (make-aux-lambda-struct name form)
   (match form
-    (('lambda ret-type arglist captures . body)
+    (('lambda arglist ret-type captures . body)
      ;; Captures are ignored for now, but
      ;; we'll need them for TODO: closures support
-     (process-fn (copy-form-source! form `(fn ,ret-type ,name ,arglist ,@body))
+     (process-fn (copy-form-source! form `(fn ,name ,arglist ,ret-type ,@body))
                  (list)))
     (else (sex-error form "malformed lambda" form))))
 
@@ -192,8 +266,9 @@
 
 ;;; Record the named structs, unions and enums in the type database
 (define (process-struct sex-struct acc)
-  (register-aggregate! sex-struct)
-  (cons sex-struct acc))
+  (let-values (((doc form) (extract-aggregate-docstring sex-struct)))
+    (register-aggregate! form)
+    (with-docstring doc form acc)))
 
 (define (register-aggregate! form)
   (let* ((f (if (eq? (car form) 'pub) (cdr form) form))
@@ -218,45 +293,36 @@
   "The `form` must be toplevel.
 Returns #f if the form is not a function, returns the form otherwise"
   (match form
-    ((fn . _) form)
-    ((pub fn . _) form)
+    ((or ('fn . _)
+         ('pub 'fn . _)
+         ('extern 'fn . _)) form)
     (else #f)))
 
 (define (sex-fn-public? fn-form)
-  (eq? (car fn-form) 'pub))
-
-(define (sex-fn-return-type fn-form)
-  (assert (sex-fn? fn-form)
-          (fmt #f "Form " fn-form " is not a function"))
-  (if (sex-fn-public? fn-form)
-      (third fn-form)
-      (second fn-form)))
+  (eq? (first fn-form) 'pub))
 
 (define (sex-fn-name fn-form)
   (assert (sex-fn? fn-form)
           (fmt #f "Form " fn-form " is not a function"))
-  (if (sex-fn-public? fn-form)
-      (fourth fn-form)
-      (third fn-form)))
+  (second (fn-core fn-form)))
 
 (define (sex-fn-arglist fn-form)
   (assert (sex-fn? fn-form)
           (fmt #f "Form " fn-form " is not a function"))
-  (if (sex-fn-public? fn-form)
-      (fifth fn-form)
-      (fourth fn-form)))
+  (third (fn-core fn-form)))
+
+(define (sex-fn-return-type fn-form)
+  (assert (sex-fn? fn-form)
+          (fmt #f "Form " fn-form " is not a function"))
+  (fourth (fn-core fn-form)))
 
 (define (sex-fn-prototype fn-form)
   "Returns all except body"
   (assert (sex-fn? fn-form)
           (fmt #f "Form " fn-form " is not a function"))
-  (if (sex-fn-public? fn-form)
-      (take fn-form 5)
-      (take fn-form 4)))
+  (take fn-form (fn-header-length fn-form)))
 
 (define (sex-fn-body fn-form)
   (assert (sex-fn? fn-form)
           (fmt #f "Form " fn-form " is not a function"))
-  (if (sex-fn-public? fn-form)
-      (drop fn-form 5)
-      (drop fn-form 4)))
+  (drop fn-form (fn-header-length fn-form)))

sex-fmt-c.scm

@@ -14,6 +14,7 @@
      c-in-expr c-in-stmt c-in-test
      c-paren c-maybe-paren c-type c-literal? c-literal char->c-char
      c-struct c-union c-class c-enum c-typedef c-cast
+     c-braced-list c-compound c-designate
      c-expr c-expr/sexp c-apply c-op c-indent c-current-indent-string
      c-wrap-stmt c-open-brace c-close-brace
      c-block c-braced-block c-begin
@@ -277,6 +278,8 @@
               ((%comment) ((apply c-comment (cdr x)) st))
               ((:) ((apply c-label (cdr x)) st))
               ((%cast) ((apply c-cast (cdr x)) st))
+              ((%compound) ((apply c-compound (cdr x)) st))
+              ((%designate) ((apply c-designate (cdr x)) st))
               ((+ - & * / % ! ~ ^ && < > <= >= == != << >>
                   = *= /= %= &= ^= >>= <<=) ; |\|| |\|\|| |\|=|
                ((apply c-op x) st))
@@ -306,17 +309,7 @@
                  ((apply c-op "-=" (cdr x)) st))
                 (else ((c-apply x) st))))))
            ((vector? x)
-            ((c-wrap-stmt
-              (fmt-try-fit
-               (fmt-let 'no-wrap? #t
-                        (cat "{" (fmt-join c-expr (vector->list x) ", ") "}"))
-               (lambda (st)
-                 (let* ((col (fmt-col st))
-                        (sep (string-append "," (make-nl-space col))))
-                   ((cat "{" (fmt-join c-expr (vector->list x) sep)
-                         "}" nl)
-                    st)))))
-             st))
+            ((c-wrap-stmt (c-braced-list (vector->list x))) st))
            (else
             ((c-literal x) st))))))
 
@@ -832,6 +825,25 @@
              (cat "(" (c-with-op 'paren (c-expr expr)) ")")
              (c-expr expr))))
 
+  ;; { a, b, c } -- on one line if it fits, one element per line if not.
+  (define (c-braced-list ls)
+    (fmt-try-fit
+     (fmt-let 'no-wrap? #t (cat "{" (fmt-join c-expr ls ", ") "}"))
+     (lambda (st)
+       (let* ((col (fmt-col st))
+              (sep (string-append "," (make-nl-space col))))
+         ((cat "{" (fmt-join c-expr ls sep) "}" nl) st)))))
+
+  ;; (T){ ... } -- a C99 compound literal, not a cast: the result is an
+  ;; unnamed object and an lvalue, so `&' on it is legal. At block scope
+  ;; it lives until the end of the enclosing block and no longer.
+  (define (c-compound type . init)
+    (cat "(" (c-type type) ")" (c-braced-list init)))
+
+  ;; .field = value, inside a braced list
+  (define (c-designate field value)
+    (cat "." (c-expr field) " = " (c-expr value)))
+
   (define (c-typedef type alias . o)
     (c-wrap-stmt
      (cat "typedef " (c-type type alias) (fmt-join/prefix c-expr o " "))))

sex-modules.scm

@@ -8,6 +8,7 @@
   (chicken process-context)
   (chicken string)
   fmt
+  matchable
   reader
   srfi-1
   utils)
@@ -71,28 +72,35 @@
      (list)
      raw-forms)))
 
+(define (public-fn-interface raw-form)
+  ;; (pub fn name args ret . body) -> prototype, keeping a docstring so
+  ;; the importer can emit it above the declaration
+  (let ((form (strip-header-comments raw-form 5)))
+    (match form
+      (('pub 'fn name args ret)
+       form)
+      (('pub 'fn name args ret ('comment . _) . rest)
+       (public-fn-interface `(pub fn ,name ,args ,ret ,@rest)))
+      (('pub 'fn name args ret (? string? doc) . _)
+       `(pub fn ,name ,args ,ret ,doc))
+      (('pub 'fn name args ret . _)
+       `(pub fn ,name ,args ,ret)))))
+
 ;;; TODO: use semen facilities to analyze modules
 (define (process-public-interface-form form acc)
-  (case (car form)
-    ((pub)
-     (case (cadr form)
-       ;; A function is reduced to a prototype and keeps its `pub', so
-       ;; the importing unit declares it with external linkage
-       ((fn)
-        (cons (copy-form-source!
-               form
-               (take (strip-header-comments form 5) 5))
-              acc))
-       ;; A variable becomes an `extern' declaration
-       ((var)
-        (cons (copy-form-source!
-               form
-               (cons 'extern (take (cdr (strip-header-comments form 4)) 3)))
-              acc))
-       ((define defmacro enum import include struct typedef union)
-        (cons (copy-form-source! form (cdr form)) acc))
-       (else (sex-error form "pub must be followed by a definition" form))))
-    (else acc)))
+  (match form
+    ;; Reduced to a prototype, still `pub', so the importer declares it
+    ;; with external linkage
+    (('pub 'fn . _)
+     (cons (copy-form-source! form (public-fn-interface form)) acc))
+    (('pub 'var . _)
+     (match-let ((('pub 'var name type . _) (strip-header-comments form 4)))
+       (cons (copy-form-source! form `(extern var ,name ,type)) acc)))
+    (('pub (or 'define 'defmacro 'enum 'import 'include 'struct 'typedef 'union) . _)
+     (cons (copy-form-source! form (cdr form)) acc))
+    (('pub . _)
+     (sex-error form "pub must be followed by a definition" form))
+    (_ acc)))
 
 (define (load-persistent-module-paths)
   (let ((sex-module-path-env-var

sexc.scm

@@ -176,6 +176,7 @@ status, which is ours to pass on."
 
 (define prelude
   '((include inttypes.h)
+    (include stdbool.h)
 
     (typedef u8 uint8-t)
     (typedef i8 int8-t)

tests/basic.scm

@@ -31,10 +31,10 @@
   (test 'vector-ref (atom-to-fmt-c '¤))
   (test '%include (atom-to-fmt-c 'include))
 
-  ;; c89 stuff
-  (test 'int (atom-to-fmt-c 'bool))
-  (test 1 (atom-to-fmt-c 'true))
-  (test 0 (atom-to-fmt-c 'false))
+  ;; C99 onwards, true C spellings for bool
+  (test 'bool (atom-to-fmt-c 'bool))
+  (test 'true (atom-to-fmt-c 'true))
+  (test 'false (atom-to-fmt-c 'false))
 
   ;; dot-access -> %. member-access directive (kebab-converted operands)
   (test '(%. a b) (walk-expr '(dot-access a b)))

tests/codegen.scm

@@ -230,4 +230,33 @@ compiles."
     (test-assert "grouping sublist still accepted"
       (emits? (in-fn "(var s (* (const struct suc)) 0)") "const struct suc * s"))
     (test-assert "flat chain still accepted"
-      (emits? (in-fn "(var q (* * const char) 0)") "const char * * q"))))
+      (emits? (in-fn "(var q (* * const char) 0)") "const char * * q")))
+
+  ;; A string as the first body form (or after the name of a struct,
+  ;; union or enum) is a docstring: it becomes a comment immediately
+  ;; before the declaration, not a statement inside it.
+  (test-group "docstrings"
+    (test-assert "appears before the function"
+      (emits? "(fn greet ((name (* char))) void \"Greet NAME.\" (printf \"hi\" name))"
+              "/* Greet NAME. */"))
+    (test-assert "and not inside the body as a statement"
+      (not (emits? "(fn greet ((name (* char))) void \"Greet NAME.\" (printf \"hi\" name))"
+                   "\"Greet NAME.\"")))
+    (test-assert "multiline keeps its paragraphs"
+      (emits? "(pub fn main () int \"Entry point.\n\nARGC and ARGV.\" (return 0))"
+              "Entry point."))
+    (test-assert "and the second paragraph too"
+      (emits? "(pub fn main () int \"Entry point.\n\nARGC and ARGV.\" (return 0))"
+              "ARGC and ARGV."))
+    (test-assert "a prototype with only a docstring stays a prototype"
+      (emits? "(fn helper ((a int)) int \"Forward.\")"
+              "helper (int a);"))
+    (test-assert "a string after the first statement is left alone"
+      (emits? "(fn f () void (g) \"not a docstring\")"
+              "\"not a docstring\""))
+    (test-assert "a struct docstring sits above the struct"
+      (emits? "(struct point \"A 2D point.\" ((x int) (y int)))"
+              "/* A 2D point. */"))
+    (test-assert "and an enum docstring too"
+      (emits? "(enum color \"RGB.\" (red green blue))"
+              "/* RGB. */"))))

tests/fmt-c-writer.scm

@@ -101,6 +101,39 @@
    '(%var (struct suc *) s (hoge piyo))
    (walk-var '(var s (* struct suc) (hoge piyo))))
 
+;;; Initializers and compound literals
+  (test "a bare initializer is unchanged"
+   '#(1 2)
+   (walk-expr '#(1 2)))
+
+  (test "`:' ends the type and makes it a compound literal"
+   '(%compound (struct point) 3 4)
+   (walk-expr '#(struct point : 3 4)))
+
+  (test "the type is bare words, as everywhere else"
+   '(%compound (const char *) 65)
+   (walk-expr '#(* const char : 65)))
+
+  (test "and may be an array type"
+   '(%compound (%array int 3) 10 20 30)
+   (walk-expr '#(¤ int 3 : 10 20 30)))
+
+  (test "a grouped type is unwrapped the way a declaration's is"
+   '(%compound (%array int 3) 10)
+   (walk-expr '#((¤ int 3) : 10)))
+
+  (test "`.field value' is a designated initializer, kebab and all"
+   '(%compound (struct named) (%designate n 7) (%designate first_name "zoe"))
+   (walk-expr '#(struct named : .n 7 .first-name "zoe")))
+
+  (test "positional and designated may be mixed"
+   '(%compound (struct point) 1 (%designate y 5))
+   (walk-expr '#(struct point : 1 .y 5)))
+
+  (test "designators work in an untyped initializer too"
+   '#((%designate y 5))
+   (walk-expr '#(.y 5)))
+
 ;;; Fn defs
   (test
    '(%fun void puk ((int) (%array float 8)))
@@ -150,7 +183,7 @@
   (test
    '(struct mega_kebab ((int a)
                         ((struct ((int year) (int month) (int day))) dob)
-                        ((%fun int ((int) (%array int))) min)))
+                        ((%fun bool ((int) (%array int))) min)))
    (walk-struct '(struct mega-kebab
                          ((a int)
                           (dob (struct ((year int)

tests/modules/greet.sex

@@ -13,7 +13,9 @@
                      ;; counted off by one
   int 0)
 
-(pub struct greeting ((text (* const char)) (times int)))
+(pub struct greeting
+  "A greeting to print."
+  ((text (* const char)) (times int)))
 
 (pub enum mood (cheerful grumpy))
 
@@ -29,6 +31,7 @@
 
 (pub fn greet ;; ...and here the prototype would lose its return type
   ((name (* const char))) void
+  "Print a greeting for NAME."
   (++ greet-count)
   (printf "hello, %s\n" name))
 

tests/semen.scm

@@ -1,30 +1,35 @@
 (import srfi-69
-        semen)
+        semen
+        types)
 
 (define print-str-fn
-  '(fn void print-str ((string s))
+  '(fn print-str ((s string)) void
        (printf "%s" s)))
 
 (define sum-fn
-  '(pub fn float sum ((int a) (int b))
-        (return (cast float (+ a b)))))
+  '(pub fn sum ((a int) (b int)) float
+        (return (cast (+ a b) float))))
 
 (test-group "semen"
   (test-assert (sex-fn? print-str-fn))
   (test #f (sex-fn-public? print-str-fn))
   (test 'void (sex-fn-return-type print-str-fn))
   (test 'print-str (sex-fn-name print-str-fn))
-  (test '((string s)) (sex-fn-arglist print-str-fn))
-  (test '(fn void print-str ((string s))) (sex-fn-prototype print-str-fn))
+  (test '((s string)) (sex-fn-arglist print-str-fn))
+  (test '(fn print-str ((s string)) void) (sex-fn-prototype print-str-fn))
   (test '((printf "%s" s)) (sex-fn-body print-str-fn))
 
   (test-assert (sex-fn? sum-fn))
   (test #t (sex-fn-public? sum-fn))
   (test 'float (sex-fn-return-type sum-fn))
   (test 'sum (sex-fn-name sum-fn))
-  (test '((int a) (int b)) (sex-fn-arglist sum-fn))
-  (test '(pub fn float sum ((int a) (int b))) (sex-fn-prototype sum-fn))
-  (test '((return (cast float (+ a b)))) (sex-fn-body sum-fn))
+  (test '((a int) (b int)) (sex-fn-arglist sum-fn))
+  (test '(pub fn sum ((a int) (b int)) float) (sex-fn-prototype sum-fn))
+  (test '((return (cast (+ a b) float))) (sex-fn-body sum-fn))
+
+  (test-assert (sex-fn? '(extern fn foo () void)))
+  (test 'foo (sex-fn-name '(extern fn foo () void)))
+  (test #f (sex-fn? '(struct point ((x int)))))
 
   (let ((sex-code
          '((defmacro (sum-var name a b c)
@@ -49,9 +54,78 @@
          '((defmacro (x10 a)
              `(* 10 ,a))
 
-           (fn void foo ((int a) (int b))
+           (fn foo ((a int) (b int)) void
                (return (+ a (x10 b)))))))
 
-    (test '((fn void foo ((int a) (int b))
+    (test '((fn foo ((a int) (b int)) void
                 (return (+ a (* 10 b)))))
-          (semen-process sex-code-macro))))
+          (semen-process sex-code-macro)))
+
+;;; Docstrings are lifted out as comment forms sitting before the
+;;; declaration. A string later in a body is left alone.
+
+  (test '((comment "Greet NAME.")
+          (fn greet ((name (* char))) void
+              (printf "Hello %s!\n" name)))
+        (semen-process
+         '((fn greet ((name (* char))) void
+               "Greet NAME."
+               (printf "Hello %s!\n" name)))))
+
+  (test '((comment "Public entry.")
+          (pub fn main () int
+               (return 0)))
+        (semen-process
+         '((pub fn main () int
+                "Public entry."
+                (return 0)))))
+
+  ;; A prototype whose only "body" is a docstring stays a prototype
+  (test '((comment "Forward.")
+          (fn helper ((a int)) int))
+        (semen-process
+         '((fn helper ((a int)) int
+               "Forward."))))
+
+  (test '((fn f () void (g) "not a docstring"))
+        (semen-process
+         '((fn f () void (g) "not a docstring"))))
+
+  ;; `;' comments before the string are skipped when looking for it,
+  ;; and stay in the body
+  (test '((comment "Kept.")
+          (fn f () void (comment " note") (g)))
+        (semen-process
+         '((fn f () void (comment " note") "Kept." (g)))))
+
+  (test '((comment "A 2D point.")
+          (struct t-doc-pt ((x int) (y int))))
+        (semen-process
+         '((struct t-doc-pt "A 2D point." ((x int) (y int))))))
+
+  (test '((x int) (y int))
+        (get-fields 't-doc-pt))
+
+  (test '((comment "RGB.")
+          (enum t-doc-color (red green blue)))
+        (semen-process
+         '((enum t-doc-color "RGB." (red green blue)))))
+
+  (test '((comment "Either.")
+          (union t-doc-val ((i int) (f float))))
+        (semen-process
+         '((union t-doc-val "Either." ((i int) (f float))))))
+
+  ;; Includes
+  (test '((include stdio.h))
+        (semen-process
+         '((include stdio.h))))
+  (test '((include stdio.h)
+          (include stdlib.h))
+        (semen-process
+         '((include stdio.h
+                    stdlib.h))))
+  (test '()
+        (semen-process
+         '((include))))
+)

tests/sex-programs/compound-literals.sex

@@ -0,0 +1,49 @@
+(input)
+(output "plain 1 2"
+        "literal 3 4"
+        "designated zoe 7"
+        "through a pointer 9"
+        "array 10 20 30"
+        "argument 6"
+        "mixed 1 5")
+(return 0)
+
+;;; `:' inside #(...) ends a type and makes the rest a C99 compound
+;;; literal. Without one, #(...) is the brace initializer it always was.
+
+(include stdio.h)
+
+(struct point ((x int) (y int)))
+(struct named ((first-name (* const char)) (n int)))
+
+(fn sum ((p (struct point))) int
+  (return (+ (. p x) (. p y))))
+
+(pub fn main () int
+  ;; unchanged: a bare initializer has no type of its own
+  (var p (struct point) #(1 2))
+  (printf "plain %d %d\n" (. p x) (. p y))
+
+  (var q (struct point) #(struct point : 3 4))
+  (printf "literal %d %d\n" (. q x) (. q y))
+
+  ;; designated, out of declaration order, and kebab-cased
+  (var r (struct named) #(struct named : .n 7 .first-name "zoe"))
+  (printf "designated %s %d\n" (. r first-name) (. r n))
+
+  ;; a compound literal is an lvalue, so its address can be taken --
+  ;; until the end of the enclosing block, and no longer
+  (var pp (* struct point) (& #(struct point : 9 9)))
+  (printf "through a pointer %d\n" (-> pp x))
+
+  ;; an array literal decays the way an array does
+  (var a (* int) #([int 3] : 10 20 30))
+  (printf "array %d %d %d\n" (¤ a 0) (¤ a 1) (¤ a 2))
+
+  (printf "argument %d\n" (sum #(struct point : 2 4)))
+
+  ;; positional and designated may be mixed, as in C
+  (var m (struct point) #(struct point : 1 .y 5))
+  (printf "mixed %d %d\n" (. m x) (. m y))
+
+  (return 0))

tests/sex-programs/feature-flags.sex

@@ -1,6 +1,6 @@
-(compilation "-f alpha --features beta --features=gamma --no-platform-features")
+(compilation "-f alpha -f beta,gamma --features=delta --no-platform-features")
 (input)
-(output "alpha" "beta" "gamma" "elsewhere")
+(output "alpha" "beta" "gamma" "delta" "elsewhere")
 (return 0)
 
 ;;; The flags naming the features, in every spelling sexc takes. This
@@ -19,6 +19,7 @@
   #+alpha (puts "alpha")
   #+beta (puts "beta")
   #+gamma (puts "gamma")
+  #+delta (puts "delta")
   #-unix (puts "elsewhere")
   #+unix (puts "here")
   (return 0))

tests/sex-programs/lambdas.sex

@@ -0,0 +1,44 @@
+(input)
+(output "Named fn through a pointer: 30"
+        "Lambda through a pointer: 30"
+        "Lambda called in place: 130"
+        "Nested lambdas: 666")
+(return 0)
+
+;;; Lambdas are lifted into toplevel functions by semen, so what this
+;;; really checks is that the lifted `fn' comes out in the argument
+;;; order the writer expects -- (fn name arglist ret-type . body).
+
+(include stdio.h)
+
+(fn sum ((a int) (b int)) int
+  (return (+ a b)))
+
+(pub fn main () int
+  (var a int 10)
+  (var b int 20)
+
+  (var sum-fn (fn ((int) (int)) int) sum)
+  (printf "Named fn through a pointer: %d\n" (sum-fn a b))
+
+  (var sum-lambda (fn ((int) (int)) int)
+       (lambda ((a int) (b int)) int ()
+         (return (+ a b))))
+  (printf "Lambda through a pointer: %d\n" (sum-lambda a b))
+
+  (printf "Lambda called in place: %d\n"
+          ((lambda ((a int) (b int)) int ()
+             (return (+ a b 100)))
+           a b))
+
+  ;; A lambda inside a lambda: the inner one is lifted out of a
+  ;; function that is itself being lifted
+  (var outer (fn ((int)) int)
+       (lambda ((x int)) int ()
+         (var inner (fn ((int)) int)
+              (lambda ((y int)) int ()
+                (return (+ 60 y))))
+         (return (+ 600 (inner x)))))
+  (printf "Nested lambdas: %d\n" (outer 6))
+
+  (return 0))