simplify juliacall further

Author: Christopher Doris

python/juliacall/__init__.py

@@ -1,16 +1,15 @@
-__version__ = '0.5.1'
+# This module gets modified by PythonCall when it is loaded, e.g. to include Core, Base
+# and Main modules.
 
-CONFIG = {}
+__version__ = '0.5.1'
 
 def newmodule(name):
     "A new module with the given name."
-    from . import Base
     return Base.Module(Base.Symbol(name))
 
 class As:
     "Interpret 'value' as type 'type' when converting to Julia."
     __slots__ = ("value", "type")
-    __module__ = "juliacall"
     def __init__(self, value, type):
         self.value = value
         self.type = type
@@ -19,24 +18,84 @@ def __repr__(self):
 
 class JuliaError(Exception):
     "An error arising in Julia code."
-    __module__ = "juliacall"
     def __init__(self, exception, stacktrace=None):
         super().__init__(exception, stacktrace)
     def __str__(self):
         e = self.exception
-        if isinstance(e, str):
-            return e
+        b = self.stacktrace
+        if b is None:
+            return Base.sprint(Base.showerror, e)
         else:
-            from . import Base
-            io = Base.IOBuffer()
-            Base.showerror(io, e)
-            return str(Base.String(Base.take_b(io)))
+            return Base.sprint(Base.showerror, e, b)
     @property
     def exception(self):
         return self.args[0]
     @property
     def stacktrace(self):
         return self.args[1]
 
-from .init import init
+CONFIG = {'inited': False}
+
+def init():
+    import os
+    import ctypes as c
+    import sys
+    import subprocess
+
+    # Determine if we should skip initialising.
+    CONFIG['noinit'] = os.getenv('PYTHON_JULIACALL_NOINIT', '') == 'yes'
+    if CONFIG['noinit']:
+        return
+
+    # Stop if we already initialised
+    if CONFIG['inited']:
+        return
+
+    # we don't import this at the top level because it is not required when juliacall is
+    # loaded by PythonCall and won't be available
+    import juliapkg
+
+    # Find the Julia executable and project
+    CONFIG['exepath'] = exepath = juliapkg.executable()
+    CONFIG['project'] = project = juliapkg.project()
+
+    # Find the Julia library
+    cmd = [exepath, '--project='+project, '--startup-file=no', '-O0', '--compile=min', '-e', 'import Libdl; print(abspath(Libdl.dlpath("libjulia")))']
+    CONFIG['libpath'] = libpath = subprocess.run(cmd, check=True, capture_output=True, encoding='utf8').stdout
+    assert os.path.exists(libpath)
+
+    # Initialise Julia
+    d = os.getcwd()
+    try:
+        # Open the library
+        os.chdir(os.path.dirname(libpath))
+        CONFIG['lib'] = lib = c.CDLL(libpath)
+        lib.jl_init__threading.argtypes = []
+        lib.jl_init__threading.restype = None
+        lib.jl_init__threading()
+        lib.jl_eval_string.argtypes = [c.c_char_p]
+        lib.jl_eval_string.restype = c.c_void_p
+        os.environ['JULIA_PYTHONCALL_LIBPTR'] = str(c.pythonapi._handle)
+        os.environ['JULIA_PYTHONCALL_EXE'] = sys.executable or ''
+        os.environ['JULIA_PYTHONCALL_PROJECT'] = project
+        script = '''
+            try
+                import Pkg
+                Pkg.activate(ENV["JULIA_PYTHONCALL_PROJECT"], io=devnull)
+                import PythonCall
+            catch err
+                print(stderr, "ERROR: ")
+                showerror(stderr, err, catch_backtrace())
+                flush(stderr)
+                rethrow()
+            end
+            '''
+        res = lib.jl_eval_string(script.encode('utf8'))
+        if res is None:
+            raise Exception('PythonCall.jl did not start properly')
+    finally:
+        os.chdir(d)
+
+    CONFIG['inited'] = True
+
 init()