A few tiny changes to slightly improve performance (#450)

 * Cache `ctx.current_ns` in the Analyzer and Generator whenever possible
 * Do not collect comprehensions into intermediate lists when they will just be put into some other iterable later
 * Use `str.translate` for munging, rather than manual translation

Nothing here moves the needle dramatically, but every little bit that shaves a few milliseconds off of the startup time helps.

Author: chrisrink10

src/basilisp/lang/compiler/analyzer.py

@@ -648,18 +648,21 @@ def _def_ast(  # pylint: disable=too-many-branches,too-many-locals
             raise AnalyzerException("def docstring must be a string", form=doc)
         children = vec.v(INIT)
 
+    # Cache the current namespace
+    current_ns = ctx.current_ns
+
     # Attach metadata relevant for the current process below.
-    def_loc = _loc(form)
+    def_loc = _loc(form) or (None, None)
     def_node_env = ctx.get_node_env()
     def_meta = _clean_meta(
         name.meta.update(
             lmap.map(
                 {
-                    COL_KW: def_loc[1] if def_loc is not None else None,
+                    COL_KW: def_loc[1],
                     FILE_KW: def_node_env.file,
-                    LINE_KW: def_loc[0] if def_loc is not None else None,
+                    LINE_KW: def_loc[0],
                     NAME_KW: name,
-                    NS_KW: ctx.current_ns,
+                    NS_KW: current_ns,
                 }
             )
         )
@@ -688,7 +691,7 @@ def _def_ast(  # pylint: disable=too-many-branches,too-many-locals
     # its meta may contain values which fail to compile.
     bare_name = sym.symbol(name.name)
 
-    ns_sym = sym.symbol(ctx.current_ns.name)
+    ns_sym = sym.symbol(current_ns.name)
     var = Var.intern_unbound(
         ns_sym,
         bare_name,
@@ -729,7 +732,7 @@ def _def_ast(  # pylint: disable=too-many-branches,too-many-locals
                         sym.symbol("Namespace", "basilisp.lang.runtime"),
                         sym.symbol("get"),
                     ),
-                    llist.l(SpecialForm.QUOTE, sym.symbol(ctx.current_ns.name)),
+                    llist.l(SpecialForm.QUOTE, sym.symbol(current_ns.name)),
                 ),
             }
         ),
@@ -1448,7 +1451,7 @@ def _fn_ast(  # pylint: disable=too-many-branches
                 fixed_arities.add(method.fixed_arity)
 
         if fixed_arity_for_variadic is not None and any(
-            [fixed_arity_for_variadic < arity for arity in fixed_arities]
+            fixed_arity_for_variadic < arity for arity in fixed_arities
         ):
             raise AnalyzerException(
                 "variadic arity may not have fewer fixed arity arguments than any other arities",
@@ -2016,7 +2019,7 @@ def _try_ast(  # pylint: disable=too-many-branches
         try_exprs.append(lisp_node)
 
     assert all(
-        [isinstance(node, Catch) for node in catches]
+        isinstance(node, Catch) for node in catches
     ), "All catch statements must be catch ops"
 
     *try_statements, try_ret = try_exprs
@@ -2242,8 +2245,9 @@ def __resolve_namespaced_symbol(  # pylint: disable=too-many-branches
     """Resolve a namespaced symbol into a Python name or Basilisp Var."""
     assert form.ns is not None
 
-    if form.ns == ctx.current_ns.name:
-        v = ctx.current_ns.find(sym.symbol(form.name))
+    current_ns = ctx.current_ns
+    if form.ns == current_ns.name:
+        v = current_ns.find(sym.symbol(form.name))
         if v is not None:
             return VarRef(form=form, var=v, env=ctx.get_node_env())
     elif form.ns == _BUILTINS_NS:
@@ -2262,7 +2266,7 @@ def __resolve_namespaced_symbol(  # pylint: disable=too-many-branches
             "symbol names may not contain the '.' operator", form=form
         )
 
-    resolved = __resolve_namespaced_symbol_in_ns(ctx, ctx.current_ns, form)
+    resolved = __resolve_namespaced_symbol_in_ns(ctx, current_ns, form)
     if resolved is not None:
         return resolved
     elif ctx.current_macro_ns is not None:
@@ -2290,7 +2294,8 @@ def __resolve_bare_symbol(
     assert form.ns is None
 
     # Look up the symbol in the namespace mapping of the current namespace.
-    v = ctx.current_ns.find(form)
+    current_ns = ctx.current_ns
+    v = current_ns.find(form)
     if v is not None:
         return VarRef(form=form, var=v, env=ctx.get_node_env())
 
@@ -2317,7 +2322,7 @@ def __resolve_bare_symbol(
     if ctx.should_allow_unresolved_symbols:
         return _const_node(ctx, form)
 
-    assert munged not in vars(ctx.current_ns.module)
+    assert munged not in vars(current_ns.module)
     raise AnalyzerException(
         f"unable to resolve symbol '{form}' in this context", form=form
     )

src/basilisp/lang/compiler/generator.py

@@ -593,10 +593,12 @@ def __should_warn_on_redef(
     no_warn_on_redef = def_meta.val_at(SYM_NO_WARN_ON_REDEF_META_KEY, False)
     if no_warn_on_redef:
         return False
-    elif safe_name in ctx.current_ns.module.__dict__:
+
+    current_ns = ctx.current_ns
+    if safe_name in current_ns.module.__dict__:
         return True
-    elif defsym in ctx.current_ns.interns:
-        var = ctx.current_ns.find(defsym)
+    elif defsym in current_ns.interns:
+        var = current_ns.find(defsym)
         assert var is not None, f"Var {defsym} cannot be none here"
 
         if var.meta is not None and var.meta.val_at(SYM_REDEF_META_KEY):

src/basilisp/lang/compiler/nodes.py

@@ -197,7 +197,7 @@ def fix_missing_locations(
             loc = (self.env.line, self.env.col)
 
         assert loc is not None and all(
-            [e is not None for e in loc]
+            e is not None for e in loc
         ), "Must specify location information"
 
         new_attrs: MutableMapping[str, Union[NodeEnv, Node, Iterable[Node]]] = {
@@ -210,10 +210,9 @@ def fix_missing_locations(
             if child_attr.endswith("s"):
                 iter_child: Iterable[Node] = getattr(self, child_attr)
                 assert iter_child is not None, "Listed child must not be none"
-                new_children = []
-                for item in iter_child:
-                    new_children.append(item.fix_missing_locations(start_loc))
-                new_attrs[child_attr] = vec.vector(new_children)
+                new_attrs[child_attr] = vec.vector(
+                    item.fix_missing_locations(start_loc) for item in iter_child
+                )
             else:
                 child: Node = getattr(self, child_attr)
                 assert child is not None, "Listed child must not be none"

src/basilisp/lang/util.py

@@ -25,20 +25,17 @@
     "&": "__AMP__",
     "$": "__DOLLAR__",
 }
+_MUNGE_TRANSLATE_TABLE = str.maketrans(_MUNGE_REPLACEMENTS)
 
 
 def count(seq: Iterable) -> int:
-    return sum([1 for _ in seq])
+    return sum(1 for _ in seq)
 
 
 def munge(s: str, allow_builtins: bool = False) -> str:
     """Replace characters which are not valid in Python symbols
     with valid replacement strings."""
-    new_str = []
-    for c in s:
-        new_str.append(_MUNGE_REPLACEMENTS.get(c, c))
-
-    new_s = "".join(new_str)
+    new_s = s.translate(_MUNGE_TRANSLATE_TABLE)
 
     if keyword.iskeyword(new_s):
         return f"{new_s}_"

tox.ini

@@ -2,7 +2,7 @@
 envlist = py36,py37,py38,pypy3,coverage,mypy,format,lint,safety
 
 [testenv]
-parallel_show_output = {env:TOX_SHOW_OUTPUT:false}
+parallel_show_output = {env:TOX_SHOW_OUTPUT:true}
 setenv =
     BASILISP_DO_NOT_CACHE_NAMESPACES = true
 deps =
@@ -17,7 +17,6 @@ commands =
              {posargs}
 
 [testenv:coverage]
-parallel_show_output = {env:TOX_SHOW_OUTPUT:false}
 depends = py36, py37, py38
 deps =
     coveralls
@@ -54,25 +53,21 @@ exclude_lines =
     if __name__ == .__main__.:
 
 [testenv:format]
-parallel_show_output = {env:TOX_SHOW_OUTPUT:false}
 deps = black
 commands =
     black --check .
 
 [testenv:mypy]
-parallel_show_output = {env:TOX_SHOW_OUTPUT:false}
 deps = mypy
 commands =
     mypy --config-file={toxinidir}/mypy.ini src/basilisp
 
 [testenv:lint]
-parallel_show_output = {env:TOX_SHOW_OUTPUT:false}
 deps = prospector==1.1.6.2
 commands =
     prospector --profile-path={toxinidir}
 
 [testenv:safety]
-parallel_show_output = {env:TOX_SHOW_OUTPUT:false}
 deps = safety
 commands =
     safety check