Add a simple completion hook

Author: tkf

src/julia_api.jl

@@ -30,4 +30,18 @@ function setattr(mod::Module, name, value)
     return nothing
 end
 
+@static if VERSION < v"0.7-"
+    completions(_a...; __k...) = String[]
+else
+    function completions(string, pos, context_module = Main)
+        ret, _, should_complete =
+            REPL.completions(string, pos, context_module)
+        if should_complete
+            return map(REPL.completion_text, ret)
+        else
+            return String[]
+        end
+    end
+end
+
 end  # module

src/replhelper/core.py

@@ -158,6 +158,10 @@ def get_api(main):
     return main._JuliaNameSpace__julia
 
 
+def get_cached_api():
+    return get_api(_Main)
+
+
 def get_main(**kwargs):
     """
     Create or get cached `Main`.
@@ -184,6 +188,11 @@ def ipython_options(**kwargs):
     c.TerminalIPythonApp.display_banner = False
     c.TerminalInteractiveShell.confirm_exit = False
 
+    from . import ipyext
+    c.InteractiveShellApp.extensions = [
+        ipyext.__name__,
+    ]
+
     return dict(user_ns=user_ns, config=c)
 
 
@@ -233,6 +242,13 @@ def revise():
         Main._JuliaNameSpace__julia.__class__ = replhelper.core.JuliaAPI
         replhelper.core._Main = Main
 
+    try:
+        replhelper.ipyext
+    except AttributeError:
+        pass
+    else:
+        reload(replhelper.ipyext)
+
     try:
         replhelper.tests
     except AttributeError:

src/replhelper/ipyext.py

@@ -0,0 +1,34 @@
+from .core import get_cached_api
+
+
+def julia_completer(julia, self, event):
+    pos = event.line.find("Main.eval")
+    if pos < 0:
+        return []
+    pos += len("Main.eval('")  # pos: beginning of Julia code
+    julia_code = event.line[pos:]
+    julia_pos = len(event.text_until_cursor) - pos
+    completions = julia.completions(julia_code, julia_pos)
+    if "." in event.symbol:
+        # When completing "Base.Enums.s" we need to add prefix "Base.Enums"
+        prefix = event.symbol.rsplit(".", 1)[0]
+        completions = [".".join((prefix, c)) for c in completions]
+    global last_completions, last_event
+    last_completions = completions
+    last_event = event
+    return completions
+# See:
+# IPython.core.completer.dispatch_custom_completer
+
+
+def _julia_completer(self, event):
+    return julia_completer(get_cached_api(), self, event)
+
+
+def load_ipython_extension(ip):
+    ip.set_hook("complete_command", _julia_completer,
+                re_key=r""".*\bMain\.eval\(["']""")
+# See:
+# https://ipython.readthedocs.io/en/stable/api/generated/IPython.core.hooks.html
+# IPython.core.interactiveshell.init_completer
+# IPython.core.completerlib (quick_completer etc.)