Poly/ML September 2010

polyml@lists.polyml.org

8 participants
11 discussions

Inspecting structures
by ramana.kumar＠gmail.com 27 Jan '16

27 Jan '16

Is there a way to look at the contents (i.e. signature) of a structure without opening it? (I suppose you could just open it then call a lot of PolyML.Compiler.forgetXXX, but that's quite tedious) Also, is it possible to retrieve the long path of an identifier in scope? Something that will, for example, take the rev in scope and say that it came from List. Finally, what about searching for an identifier that would come into scope if you opened some structures?

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[Fwd: Re: [polyml] Building Poly/ML on MacOS X 10.6]
by rda＠lemma-one.com 29 Dec '14

29 Dec '14

I wrote: > I am completely baffled. I thought I hada solved all my problems on > MacOS X > 10.6 and was just tidying up, when I had to recompile a 32 bit > version of > Poly/ML to test a tidied up make file. This failed because > PolyML.Compiler.printTypesWithStructureName no longer exists. The same > problem happened when i rebuild a 64 bit version. What has happened? but it was a false alarm: my make file was wrong for other reasons and the absence of PolyML.Compiler.printTypesWithStructureName was not relevant. No doubt there are good reasons why this variable has been withdrawn. Regards, Rob.

3 6

St9bad_alloc with Memory Limits near 2^n GB
by tjark.weber＠gmx.de 25 Oct '10

25 Oct '10

Running Poly/ML 5.4 on a 64-bit Linux machine with 16 GB of physical RAM, I see unexpected St9bad_alloc exceptions when I use ulimit -v with limits near 8 GB/4 GB/2 GB/1 GB. For instance, $ uname -a Linux weber 2.6.34.6-54.fc13.x86_64 #1 SMP Sun Sep 5 17:16:27 UTC 2010 x86_64 x86_64 x86_64 GNU/Linux $ poly -v Poly/ML 5.4 Release RTS version: X86_64-5.4.0 $ ulimit -v 8388608 $ poly terminate called after throwing an instance of 'St9bad_alloc' what(): std::bad_alloc Aborted (core dumped) $ ulimit -v 4321280 $ poly terminate called after throwing an instance of 'St9bad_alloc' what(): std::bad_alloc Aborted (core dumped) $ ulimit -v 2170880 $ poly terminate called after throwing an instance of 'St9bad_alloc' what(): std::bad_alloc Aborted (core dumped) $ ulimit -v 1146880 $ poly terminate called after throwing an instance of 'St9bad_alloc' what(): std::bad_alloc Aborted (core dumped) The same problem is present in Poly/ML 5.3. Any help would be appreciated. Regards, Tjark

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Low-level C FFI: call_sym or call_sym_and_convert?
by phil.clayton＠lineone.net 21 Sep '10

21 Sep '10

Hi David, I'm about to start generating code that makes calls to C via the low-level FFI. I was planning to use a form where parameters that provide return values are temporary vols created by alloc, as shown in the example SML code below (as suggested in the C interface documentation). However, it appears that the high-level FFI implementation doesn't do things this way - it uses call_sym_and_convert. Is that more efficient and should I be looking at that? Using the alloc form works when a parameter is both and input and an output: in the example C code below, the second parameter `pos` is an in-out. I notice that call_sym_and_convert doesn't have an InOut constructor for Union.directedArg. This appears to be a problem for ML types that are not a vol (i.e. not passed by reference in the C FFI) such as int. Is there a way around this? Thanks, Phil /* -- C -- */ #include <string.h> #define TRUE (0 == 0) #define FALSE (0 != 0) /* get_next (s, pos, c) copies the character at offset pos in string s * to c, increments pos and returns TRUE, if pos is a valid index into s. * If pos is not a valid index, the function returns FALSE without * incrementing pos or writing to c. */ int get_next (const char *s, /* in */ int *pos, /* in out */ char *c) /* out */ { int len = strlen (s); if (0 <= *pos && *pos < len) { *c = s[*pos]; (*pos)++; return TRUE; } else { return FALSE; } } (* -- SML -- *) open CInterface val lib = load_lib "testlib.so.1" val (fromCbool, toCbool, Cbool) = breakConversion BOOL val Cstring = Cpointer Cchar val get_next = fn (in1, in2) => let val sym = load_sym lib "get_next" val tmp2 = alloc 1 Cint val tmp3 = alloc 1 Cchar val () = assign Cint tmp2 (toCint in2) val args = [ (Cstring, toCstring in1), (Cpointer Cint, address tmp2), (Cpointer Cchar, address tmp3) ] val res = fromCbool (call_sym sym args Cbool) val out2 = fromCint tmp2 val out3 = fromCchar tmp3 in (res, out2, out3) end; get_next ("hello", 0); get_next ("hello", 1); get_next ("hello", 2); get_next ("hello", 3); get_next ("hello", 4); get_next ("hello", 5); (* Poly/ML output *) ... val it = (true, 1, #"h"): bool * int * char val it = (true, 2, #"e"): bool * int * char val it = (true, 3, #"l"): bool * int * char val it = (true, 4, #"l"): bool * int * char val it = (true, 5, #"o"): bool * int * char val it = (false, 5, #"\^@"): bool * int * char

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Questions on the code trees of functors
by xyly781＠gmail.com 14 Sep '10

14 Sep '10

Dear David, I'm trying to understand the IR of functors in Poly/ML, and I got a few questions here: 1. I tried the following example: signature A = sig type element end signature B = sig type element end functor myfctor(s: A) :> B = struct type element = s.element end which corresponds to the following code tree: BLOCK(DECL #1{0 uses} = LAMBDAONLYINLINE( myfctor CL=false CR=0 LEV=0 LOCALS=0 ARGS=G ARGLIVES= RES=G CLOS=() BLOCK(DECL #1{0 uses} = BLOCK(DECL #2{0 uses} = INDIRECT(0, PARAM(0,1)); RECCONSTR(INDIRECT(0, LOCAL(0,2)), POLY_SYS_alloc_store G $(LIT1 G, LIT40 G, POLY_SYS_load_word G $(INDIRECT(1, LOCAL(0,2)) G, LIT0 G) G ), INDIRECT(2, LOCAL(0,2)), INDIRECT(3, LOCAL(0,2)) ) ); BLOCK(RECCONSTR(LOCAL(0,1))) )){LAMBDA}; RECCONSTR(LOCAL(0,1)) ) >From above, I understand that functor is compiled to a lambda expression. But I don't quite see what the body of the lambda expression does. From my understanding, here PARAM(0, 1) refers to the input structure s which is a tuple. However, what does the values of INDIRECT(0, LOCAL(0,2)) INDIRECT(1, LOCAL(0,2)) INDIRECT(2, LOCAL(0,2)) INDIRECT(3, LOCAL(0,2)) represent? For example, from the printing of the IR of a structure whose type is A is the following: > structure foo : A = # struct # type element = int # end; BLOCK(DECL #1{0 uses} = LIT0; RECCONSTR(LOCAL(0,1))) structure foo : A Since the tuple returned in the last statement only contains only one local variable whose value is LIT0, why we could use index 1, 2, 3 above to access other elements in the tuple? And may I also ask you what does the following code in the above codetree do, and why it does that? POLY_SYS_alloc_store G $(LIT1 G, LIT40 G, POLY_SYS_load_word G $(INDIRECT(1, LOCAL(0,2)) G, LIT0 G) G ) 2. Later I tried to add more content which is a type implemented by a list: signature A = sig type element end signature B = sig type element type set end functor myfctor(s: A) :> B = struct type element = s.element type set = element list end The printed codetree looks similar to the one given in 1, except the corresponding IR for type set = element list, which is: DECL #3{0 uses} = BLOCK(RECCONSTR(LIT0, POLY_SYS_alloc_store G $(LIT1 G, LIT40 G, LAMBDA( print-list CL=false CR=0 LEV=0 LOCALS=0 ARGS=G ARGLIVES= RES=G CLOS=() POLY_SYS_load_word G $(GLOBAL (LIT <long>, NIL ) (*GLOBAL*) G, LIT0 G) G $(RECCONSTR(LIT0, LAMBDA( print-element CL=false CR=0 LEV=0 LOCALS=0 ARGS=G ARGLIVES= RES=G CLOS=() POLY_SYS_load_word G $(INDIRECT(1, INDIRECT(0, PARAM(2,1))) G, LIT0 G ) G $(PARAM(0,1) G)){LAMBDA}, INDIRECT(2, INDIRECT(0, PARAM(1,1))), INDIRECT(3, INDIRECT(0, PARAM(1,1))) ) G ) G $(PARAM(0,1) G)){LAMBDA} G ), GLOBAL (FUN "boxed-list", LAMBDAINLINE( boxed-list CL=false CR=0 LEV=0 LOCALS=0 ARGS=G ARGLIVES= RES=G CLOS=() LIT3){LAMBDA} ) (*GLOBAL*){early} G $(RECCONSTR(LIT0, LIT0, INDIRECT(2, INDIRECT(0, PARAM(0,1))), LIT1) G ), GLOBAL (FUN "size-list", LAMBDAINLINE( size-list CL=false CR=0 LEV=0 LOCALS=0 ARGS=G ARGLIVES= RES=G CLOS=() LIT1){LAMBDA} ) (*GLOBAL*){early} G $(RECCONSTR(LIT0, LIT0, LIT0, INDIRECT(3, INDIRECT(0, PARAM(0,1)))) G ) ) ); Here why there are two more functions "size-list" and "boxed-list" appended to the end of code tree? Sorry for making this email too long, and thank you very much for your help! -- Yue

2 1

Pretty-printing of infix constructors
by rda＠lemma-one.com 08 Sep '10

08 Sep '10

I have a small issue with the Poly/ML pretty-printer. If you run: datatype FOO = D of (int * int); infix D; 1 D 2; Poly/ML prints: val it = D (1, 2) : FOO Poly/ML will parse D(1, 2) but only because of a non-standard extension that lets you omit the keyword "op" that the Standard ML definition requires before infix operator names used with ordinary function application syntax. Regards, Rob.

3 3

Names in initial top-level environment
by phil.clayton＠lineone.net 07 Sep '10

07 Sep '10

I've just noticed that the Poly/ML top-level initially has the names it unused bound to (). However unlikely, this could be accidentally exploited resulting in less portable code. Otherwise, all top-level value names are as per http://www.standardml.org/Basis/top-level-chapter.html (I suspect the basis library source just needs a few more 'val ()' bindings.) Phil

2 1

Poly/ML 5.4 Released
by David.Matthews＠prolingua.co.uk 05 Sep '10

05 Sep '10

I've uploaded version 5.4 to SourceForge and updated the web site. Thanks to everyone for your bug reports and comments. David

1 1

Interfaces for printing IR and generated code
by xyly781＠gmail.com 05 Sep '10

05 Sep '10

Dear David, As you mentioned previously, Poly/ML first compiles ML program into the IR, which is further passed to a code generator to produce low level code. I was trying to understand and document the semantics of the opcode set used by Poly/ML's interpreter, and I'm wondering whether inside Poly/ML's compiler, there are such debugging functions which could print out the IR tree as well as the generated op code for an input ML program? These functions would help me a lot to test my understanding on Poly's IR data structure and code generation. Thank you very much! Best, Yue

2 7

function for input from stdin
by johan＠hanwei.xs4all.nl 01 Sep '10

01 Sep '10

Hello, I am trying to learn SML, but drowning in its streams. The following function does what I want in SML/NJ, but not in PolySML. Is the function wrong, but SML/NJ lenient and PolySML not? If the function is wrong, what is the best way to get input from stdin without a newline? fun askName () = let val a = TextIO.inputLine TextIO.stdIn val b = String.translate (fn x => case x of #"\n" => ""|_ => str(x)) in case a of SOME("\n") => NONE | SOME(s) => SOME (b s) | NONE => NONE end Thanks Johan

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Poly/ML September 2010