Error building Snake example

[Stiivi]

When running make in the Snake example the following build error occurs:

[...]Terminal.cpp:38:10: fatal error: 'vmobjects/VMObject.h' file not
      found
#include <vmobjects/VMObject.h>
         ^~~~~~~~~~~~~~~~~~~~~~
1 error generated.
make: *** [Terminal.csp] Error 1

When I change the ROOT_DIR in the Makefile to point into the correct src path:

ROOT_DIR    ?= $(PWD)/../../..  

I am getting:

g++ -Wno-endif-labels -O2  -I/Users/stefan/Developer/Sources/SOMpp/core-lib/Examples/Snake/../../../src -enable-auto-import -L/Use
rs/stefan/Developer/Sources/SOMpp/core-lib/Examples/Snake/../../.. -shared -g \
                /Users/stefan/Developer/Sources/SOMpp/core-lib/Examples/Snake/Terminal.cpp -o Terminal.csp 
In file included from /Users/stefan/Developer/Sources/SOMpp/core-lib/Examples/Snake/Terminal.cpp:38:
In file included from /Users/stefan/Developer/Sources/SOMpp/core-lib/Examples/Snake/../../../src/vmobjects/VMObject.h:33:
/Users/stefan/Developer/Sources/SOMpp/core-lib/Examples/Snake/../../../src/vmobjects/AbstractObject.h:78:41: error: unknown type
      name 'HEAP_CLS'
    void* operator new(size_t numBytes, HEAP_CLS* heap,
                                        ^
/Users/stefan/Developer/Sources/SOMpp/core-lib/Examples/Snake/../../../src/vmobjects/AbstractObject.h:79:47: error: unexpected end
      of default argument expression
            unsigned long additionalBytes = 0 ALLOC_OUTSIDE_NURSERY_DECL) {
                                              ^~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /Users/stefan/Developer/Sources/SOMpp/core-lib/Examples/Snake/Terminal.cpp:38:
/Users/stefan/Developer/Sources/SOMpp/core-lib/Examples/Snake/../../../src/vmobjects/VMObject.h:96:41: error: unknown type name
      'HEAP_CLS'
    void* operator new(size_t numBytes, HEAP_CLS* heap, unsigned long additionalBytes = 0 ALLOC_OUTSIDE_NURSERY_DECL) {
                                        ^
/Users/stefan/Developer/Sources/SOMpp/core-lib/Examples/Snake/../../../src/vmobjects/VMObject.h:96:91: error: unexpected end of
      default argument expression
    void* operator new(size_t numBytes, HEAP_CLS* heap, unsigned long additionalBytes = 0 ALLOC_OUTSIDE_NURSERY_DECL) {
                                                                                          ^~~~~~~~~~~~~~~~~~~~~~~~~~
[... more errors ...]

fatal error: too many errors emitted, stopping now [-ferror-limit=]
20 errors generated.
make: *** [Terminal.csp] Error 1

What might be wrong?

[smarr]

I fear, that Snake extension hasn't received any love, likely since 2012.
So, the build system isn't matching anymore what SOM++ does at the moment.
Especially the switch to CMake has likely consequences.

The ROOT_DIR is probably a good start.
But there might be the assumption that it is called from another Makefile, the one for SOM++.

And there might also be further linking issues down the road: https://github.com/SOM-st/SOM/blob/5eac3287df98d54a72e4f04e0f8b5f53077da9a2/Examples/Snake/Makefile#L32

The concrete errors you see are very likely a consequence of some configuration not being set as expected.
The SOM++ build system configures for instance the type of GC and other details, which here isn't really incorporated.

I doubt I'll find the time to look into this in more detail today.
But I can probably give more pointers if you feel like taking a stab at it.

[Stiivi]

If that is the case, that it needs more time to fix it, I don't necessarily need to run the Snake example. I am just looking at any example that shows how SOMpp can be used as a library or as a module.

[smarr]

Hm, the Snake example is more of an example to demonstrate how the SOM++ interpreter can be extended with "primitives".

The Terminal.som file uses for instance getChar = primitive to read user input. (It's a small game for the terminal)
https://github.com/SOM-st/SOM/blob/5eac3287df98d54a72e4f04e0f8b5f53077da9a2/Examples/Snake/Terminal.som#L54

I haven't tried using SOM++ as library embedded into another application before.
While it is a reasonably small interpreter, no efforts have been made so far, to make embedding particularly easy.