How to build with Mac Clang 12?

[rhzs]

Hi,

I tried to build this awesome project, but got disappointing error. Would you be able to help me?

cppfront 
❯ clang source/cppfront.cpp -std=c++20 -o cppfront
In file included from source/cppfront.cpp:18:
In file included from source/sema.h:21:
source/parse.h:150:5: error: use of class template 'String' requires template arguments; argument deduction not allowed in template parameter
    String   Name,
    ^~~~~~
source/common.h:211:8: note: template is declared here
struct String
       ^
In file included from source/cppfront.cpp:18:
In file included from source/sema.h:21:
source/parse.h:201:64: error: value of type 'const char [6]' is not implicitly convertible to 'int'
using is_as_expression_node          = binary_expression_node< "is-as"          , prefix_expression_node         >;
                                                               ^~~~~~~
source/parse.h:202:83: error: unknown type name 'is_as_expression_node'; did you mean 'id_expression_node'?
using multiplicative_expression_node = binary_expression_node< "multiplicative" , is_as_expression_node          >;
                                                                                  ^~~~~~~~~~~~~~~~~~~~~
                                                                                  id_expression_node
source/parse.h:110:8: note: 'id_expression_node' declared here
struct id_expression_node;
       ^
source/parse.h:202:64: error: value of type 'const char [15]' is not implicitly convertible to 'int'
using multiplicative_expression_node = binary_expression_node< "multiplicative" , is_as_expression_node          >;
                                                               ^~~~~~~~~~~~~~~~
source/parse.h:203:83: error: use of undeclared identifier 'multiplicative_expression_node'
using additive_expression_node       = binary_expression_node< "additive"       , multiplicative_expression_node >;
                                                                                  ^
source/parse.h:204:83: error: use of undeclared identifier 'additive_expression_node'
using shift_expression_node          = binary_expression_node< "shift"          , additive_expression_node       >;
                                                                                  ^
source/parse.h:205:83: error: unknown type name 'shift_expression_node'; did you mean 'id_expression_node'?
using compare_expression_node        = binary_expression_node< "compare"        , shift_expression_node          >;
                                                                                  ^~~~~~~~~~~~~~~~~~~~~
                                                                                  id_expression_node
source/parse.h:110:8: note: 'id_expression_node' declared here
struct id_expression_node;
       ^
source/parse.h:205:64: error: value of type 'const char [8]' is not implicitly convertible to 'int'
using compare_expression_node        = binary_expression_node< "compare"        , shift_expression_node          >;
                                                               ^~~~~~~~~
source/parse.h:206:83: error: use of undeclared identifier 'compare_expression_node'
using relational_expression_node     = binary_expression_node< "relational"     , compare_expression_node        >;
                                                                                  ^
source/parse.h:207:83: error: use of undeclared identifier 'relational_expression_node'
using equality_expression_node       = binary_expression_node< "equality"       , relational_expression_node     >;
                                                                                  ^
source/parse.h:208:83: error: use of undeclared identifier 'equality_expression_node'; did you mean 'binary_expression_node'?
using bit_and_expression_node        = binary_expression_node< "bit-and"        , equality_expression_node       >;
                                                                                  ^~~~~~~~~~~~~~~~~~~~~~~~
                                                                                  binary_expression_node
source/parse.h:153:8: note: 'binary_expression_node' declared here
struct binary_expression_node
       ^
source/parse.h:208:83: error: use of undeclared identifier 'equality_expression_node'
using bit_and_expression_node        = binary_expression_node< "bit-and"        , equality_expression_node       >;
                                                                                  ^
source/parse.h:209:83: error: use of undeclared identifier 'bit_and_expression_node'; did you mean 'binary_expression_node'?
using bit_xor_expression_node        = binary_expression_node< "bit-xor"        , bit_and_expression_node        >;
                                                                                  ^~~~~~~~~~~~~~~~~~~~~~~
                                                                                  binary_expression_node
source/parse.h:153:8: note: 'binary_expression_node' declared here
struct binary_expression_node
       ^
source/parse.h:209:83: error: use of undeclared identifier 'bit_and_expression_node'
using bit_xor_expression_node        = binary_expression_node< "bit-xor"        , bit_and_expression_node        >;
                                                                                  ^
source/parse.h:210:83: error: use of undeclared identifier 'bit_xor_expression_node'; did you mean 'binary_expression_node'?
using bit_or_expression_node         = binary_expression_node< "bit-or"         , bit_xor_expression_node        >;
                                                                                  ^~~~~~~~~~~~~~~~~~~~~~~
                                                                                  binary_expression_node
source/parse.h:153:8: note: 'binary_expression_node' declared here
struct binary_expression_node
       ^
source/parse.h:210:83: error: use of undeclared identifier 'bit_xor_expression_node'
using bit_or_expression_node         = binary_expression_node< "bit-or"         , bit_xor_expression_node        >;
                                                                                  ^
source/parse.h:211:83: error: use of undeclared identifier 'bit_or_expression_node'; did you mean 'binary_expression_node'?
using logical_and_expression_node    = binary_expression_node< "logical-and"    , bit_or_expression_node         >;
                                                                                  ^~~~~~~~~~~~~~~~~~~~~~
                                                                                  binary_expression_node
source/parse.h:153:8: note: 'binary_expression_node' declared here
struct binary_expression_node
       ^
source/parse.h:211:83: error: use of undeclared identifier 'bit_or_expression_node'
using logical_and_expression_node    = binary_expression_node< "logical-and"    , bit_or_expression_node         >;
                                                                                  ^
source/parse.h:212:83: error: use of undeclared identifier 'logical_and_expression_node'
using logical_or_expression_node     = binary_expression_node< "logical-or"     , logical_and_expression_node    >;
                                                                                  ^
fatal error: too many errors emitted, stopping now [-ferror-limit=]
20 errors generated.

clang

❯ clang --version
Apple clang version 12.0.5 (clang-1205.0.22.11)
Target: x86_64-apple-darwin20.4.0
Thread model: posix
InstalledDir: /Library/Developer/CommandLineTools/usr/bin

[filipsajdak]

Replace clang with clang++

Instead of:

clang source/cppfront.cpp -std=c++20 -o cppfront

use

clang++ source/cppfront.cpp -std=c++20 -o cppfront

[filipsajdak]

Please be aware that you might have issues with compiling the code that cppfront will generate - you will need #16 to correct some includes in cpp2utils.h

[rhzs]

Please be aware that you might have issues with compiling the code that cppfront will generate - you will need #16 to correct some includes in cpp2utils.h

I did what you suggested. It's still giving me the same error.

❯ clang++ source/cppfront.cpp -std=c++20 -o cppfront
In file included from source/cppfront.cpp:18:
In file included from source/sema.h:21:
source/parse.h:150:5: error: use of class template 'String' requires template arguments; argument deduction not allowed in template parameter
    String   Name,
    ^~~~~~
source/common.h:211:8: note: template is declared here
struct String
       ^
In file included from source/cppfront.cpp:18:
In file included from source/sema.h:21:
source/parse.h:201:64: error: value of type 'const char [6]' is not implicitly convertible to 'int'
using is_as_expression_node          = binary_expression_node< "is-as"          , prefix_expression_node         >;
                                                               ^~~~~~~
source/parse.h:202:83: error: unknown type name 'is_as_expression_node'; did you mean 'id_expression_node'?
using multiplicative_expression_node = binary_expression_node< "multiplicative" , is_as_expression_node          >;
                                                                                  ^~~~~~~~~~~~~~~~~~~~~
                                                                                  id_expression_node
source/parse.h:110:8: note: 'id_expression_node' declared here
struct id_expression_node;
       ^
source/parse.h:202:64: error: value of type 'const char [15]' is not implicitly convertible to 'int'
using multiplicative_expression_node = binary_expression_node< "multiplicative" , is_as_expression_node          >;
                                                               ^~~~~~~~~~~~~~~~
source/parse.h:203:83: error: use of undeclared identifier 'multiplicative_expression_node'
using additive_expression_node       = binary_expression_node< "additive"       , multiplicative_expression_node >;
                                                                                  ^
source/parse.h:204:83: error: use of undeclared identifier 'additive_expression_node'
using shift_expression_node          = binary_expression_node< "shift"          , additive_expression_node       >;
                                                                                  ^
source/parse.h:205:83: error: unknown type name 'shift_expression_node'; did you mean 'id_expression_node'?
using compare_expression_node        = binary_expression_node< "compare"        , shift_expression_node          >;
                                                                                  ^~~~~~~~~~~~~~~~~~~~~
                                                                                  id_expression_node
source/parse.h:110:8: note: 'id_expression_node' declared here
struct id_expression_node;
       ^
source/parse.h:205:64: error: value of type 'const char [8]' is not implicitly convertible to 'int'
using compare_expression_node        = binary_expression_node< "compare"        , shift_expression_node          >;
                                                               ^~~~~~~~~
source/parse.h:206:83: error: use of undeclared identifier 'compare_expression_node'
using relational_expression_node     = binary_expression_node< "relational"     , compare_expression_node        >;
                                                                                  ^
source/parse.h:207:83: error: use of undeclared identifier 'relational_expression_node'
using equality_expression_node       = binary_expression_node< "equality"       , relational_expression_node     >;
                                                                                  ^
source/parse.h:208:83: error: use of undeclared identifier 'equality_expression_node'; did you mean 'binary_expression_node'?
using bit_and_expression_node        = binary_expression_node< "bit-and"        , equality_expression_node       >;
                                                                                  ^~~~~~~~~~~~~~~~~~~~~~~~
                                                                                  binary_expression_node
source/parse.h:153:8: note: 'binary_expression_node' declared here
struct binary_expression_node
       ^
source/parse.h:208:83: error: use of undeclared identifier 'equality_expression_node'
using bit_and_expression_node        = binary_expression_node< "bit-and"        , equality_expression_node       >;
                                                                                  ^
source/parse.h:209:83: error: use of undeclared identifier 'bit_and_expression_node'; did you mean 'binary_expression_node'?
using bit_xor_expression_node        = binary_expression_node< "bit-xor"        , bit_and_expression_node        >;
                                                                                  ^~~~~~~~~~~~~~~~~~~~~~~
                                                                                  binary_expression_node
source/parse.h:153:8: note: 'binary_expression_node' declared here
struct binary_expression_node
       ^
source/parse.h:209:83: error: use of undeclared identifier 'bit_and_expression_node'
using bit_xor_expression_node        = binary_expression_node< "bit-xor"        , bit_and_expression_node        >;
                                                                                  ^
source/parse.h:210:83: error: use of undeclared identifier 'bit_xor_expression_node'; did you mean 'binary_expression_node'?
using bit_or_expression_node         = binary_expression_node< "bit-or"         , bit_xor_expression_node        >;
                                                                                  ^~~~~~~~~~~~~~~~~~~~~~~
                                                                                  binary_expression_node
source/parse.h:153:8: note: 'binary_expression_node' declared here
struct binary_expression_node
       ^
source/parse.h:210:83: error: use of undeclared identifier 'bit_xor_expression_node'
using bit_or_expression_node         = binary_expression_node< "bit-or"         , bit_xor_expression_node        >;
                                                                                  ^
source/parse.h:211:83: error: use of undeclared identifier 'bit_or_expression_node'; did you mean 'binary_expression_node'?
using logical_and_expression_node    = binary_expression_node< "logical-and"    , bit_or_expression_node         >;
                                                                                  ^~~~~~~~~~~~~~~~~~~~~~
                                                                                  binary_expression_node
source/parse.h:153:8: note: 'binary_expression_node' declared here
struct binary_expression_node
       ^
source/parse.h:211:83: error: use of undeclared identifier 'bit_or_expression_node'
using logical_and_expression_node    = binary_expression_node< "logical-and"    , bit_or_expression_node         >;
                                                                                  ^
source/parse.h:212:83: error: use of undeclared identifier 'logical_and_expression_node'
using logical_or_expression_node     = binary_expression_node< "logical-or"     , logical_and_expression_node    >;
                                                                                  ^
fatal error: too many errors emitted, stopping now [-ferror-limit=]
20 errors generated.

[marzojr]

This is an Apple issue: for some reason, they decided that their version of clang was different enough to warrant their own versioning scheme, but not different enough to deserve a different name. The version number reported by Apple Clang is not the same as the version of the underlying LLVM/clang version: in fact, Apple Clang version 12.0.5 is actually clang 11.1.0, which does not fully support everything that this project requires.

You will probably either need to install clang from HomeBrew or MacPorts, or upgrade to XCode at least 13.0 in order to get an Apple Clang corresponding to clang 12. Here is a reference for the version numbers: note the "LLVM" and "Clang version string" columns.

[hsutter]

Thanks for asking! Yes, as others have pointed out, String requires a (mostly-)C++20 compiler. I noticed this same thing on a different downlevel compiler, and took a quick look at rewriting it to satisfy that compiler, but ended up not making a change since the current code is recognized by the three major reasonably-current compilers so this problem should age out as newrer C++20-compliant compilers are adopted.

[hsutter]

(If I'm missing something please just open a new issue to get this back on my radar, if the existing code doesn't work on g++ 10 or better, clang++ 12 (actual 12 not XCode 12) or better, and MSVC 2022 or better.)