Add a command-line option --repl-output-fn (especially for hy.contrib.hy-repr)

docs/contrib/hy_repr.rst

@@ -5,7 +5,13 @@ Hy representations
 .. versionadded:: 0.13.0
 
 ``hy.contrib.hy-repr`` is a module containing a single function.
-To import it, say ``(import [hy.contrib.hy-repr [hy-repr]])``.
+To import it, say::
+
+  (import [hy.contrib.hy-repr [hy-repr]])
+
+To make the Hy REPL use it for output, invoke Hy like so::
+
+  $ hy --repl-output-fn=hy.contrib.hy-repr.hy-repr
 
 .. _hy-repr-fn:
 

docs/tutorial.rst

@@ -193,7 +193,6 @@ Hy.  Let's experiment with this in the hy interpreter::
   [1, 2, 3]
   => {"dog" "bark"
   ... "cat" "meow"}
-  ...
   {'dog': 'bark', 'cat': 'meow'}
   => (, 1 2 3)
   (1, 2, 3)
@@ -204,6 +203,20 @@ Hy.  Let's experiment with this in the hy interpreter::
 
 Notice the last two lines: Hy has a fraction literal like Clojure.
 
+If you start Hy like this (a shell alias might be helpful)::
+
+  $ hy --repl-output-fn=hy.contrib.hy-repr.hy-repr
+
+the interactive mode will use :ref:`_hy-repr-fn` instead of Python's
+native ``repr`` function to print out values, so you'll see values in
+Hy syntax rather than Python syntax::
+
+  => [1 2 3]
+  [1 2 3]
+  => {"dog" "bark"
+  ... "cat" "meow"}
+  {"dog" "bark" "cat" "meow"}
+
 If you are familiar with other Lisps, you may be interested that Hy
 supports the Common Lisp method of quoting:
 

hy/cmdline.py

@@ -32,14 +32,16 @@ import code
 import ast
 import sys
 import os
+import importlib
 
 import astor.codegen
 
 import hy
 
 from hy.lex import LexException, PrematureEndOfInput, tokenize
-from hy.compiler import hy_compile, HyTypeError
+from hy.lex.parser import hy_symbol_mangle
-from hy.importer import (ast_compile, import_buffer_to_module,
+from hy.compiler import HyTypeError
+from hy.importer import (hy_eval, import_buffer_to_module,
                          import_file_to_ast, import_file_to_hst,
                          import_buffer_to_ast, import_buffer_to_hst)
 from hy.completer import completion
@@ -73,25 +75,35 @@ builtins.quit = HyQuitter('quit')
 builtins.exit = HyQuitter('exit')
 
 
-def print_python_code(_ast):
-    # astor cannot handle ast.Interactive, so disguise it as a module
-    _ast_for_print = ast.Module()
-    _ast_for_print.body = _ast.body
-    print(astor.codegen.to_source(_ast_for_print))
-
-
 class HyREPL(code.InteractiveConsole):
-    def __init__(self, spy=False, locals=None, filename="<input>"):
+    def __init__(self, spy=False, output_fn=None, locals=None,
+                 filename="<input>"):
+
         self.spy = spy
+
+        if output_fn is None:
+            self.output_fn = repr
+        elif callable(output_fn):
+            self.output_fn = output_fn
+        else:
+            f = hy_symbol_mangle(output_fn)
+            if "." in output_fn:
+                module, f = f.rsplit(".", 1)
+                self.output_fn = getattr(importlib.import_module(module), f)
+            else:
+                self.output_fn = __builtins__[f]
+
         code.InteractiveConsole.__init__(self, locals=locals,
                                          filename=filename)
 
     def runsource(self, source, filename='<input>', symbol='single'):
         global SIMPLE_TRACEBACKS
+        try:
             try:
                 tokens = tokenize(source)
             except PrematureEndOfInput:
                 return True
+            tokens = tokenize("(do " + source + "\n)")
         except LexException as e:
             if e.source is None:
                 e.source = source
@@ -100,10 +112,15 @@ class HyREPL(code.InteractiveConsole):
             return False
 
         try:
-            _ast = hy_compile(tokens, "__console__", root=ast.Interactive)
+            def ast_callback(main_ast, expr_ast):
                 if self.spy:
-                print_python_code(_ast)
+                    # Mush the two AST chunks into a single module for
-            code = ast_compile(_ast, filename, symbol)
+                    # conversion into Python.
+                    new_ast = ast.Module(main_ast.body +
+                                         [ast.Expr(expr_ast.body)])
+                    print(astor.to_source(new_ast))
+            value = hy_eval(tokens[0], self.locals, "__console__",
+                            ast_callback)
         except HyTypeError as e:
             if e.source is None:
                 e.source = source
@@ -117,7 +134,12 @@ class HyREPL(code.InteractiveConsole):
             self.showtraceback()
             return False
 
-        self.runcode(code)
+        if value is not None:
+            # Make the last non-None value available to
+            # the user as `_`.
+            self.locals['_'] = value
+            # Print the value.
+            print(self.output_fn(value))
         return False
 
 
@@ -211,7 +233,7 @@ def run_file(filename):
     return 0
 
 
-def run_repl(hr=None, spy=False):
+def run_repl(hr=None, **kwargs):
     import platform
     sys.ps1 = "=> "
     sys.ps2 = "... "
@@ -221,7 +243,7 @@ def run_repl(hr=None, spy=False):
     with completion(Completer(namespace)):
 
         if not hr:
-            hr = HyREPL(spy, namespace)
+            hr = HyREPL(locals=namespace, **kwargs)
 
         hr.interact("{appname} {version} using "
                     "{py}({build}) {pyversion} on {os}".format(
@@ -236,8 +258,8 @@ def run_repl(hr=None, spy=False):
     return 0
 
 
-def run_icommand(source, spy=False):
+def run_icommand(source, **kwargs):
-    hr = HyREPL(spy)
+    hr = HyREPL(**kwargs)
     if os.path.exists(source):
         with open(source, "r") as f:
             source = f.read()
@@ -272,7 +294,9 @@ def cmdline_handler(scriptname, argv):
         help="program passed in as a string, then stay in REPL")
     parser.add_argument("--spy", action="store_true",
                         help="print equivalent Python code before executing")
-
+    parser.add_argument("--repl-output-fn",
+                        help="function for printing REPL output "
+                             "(e.g., hy.contrib.hy-repr.hy-repr)")
     parser.add_argument("-v", "--version", action="version", version=VERSION)
 
     parser.add_argument("--show-tracebacks", action="store_true",
@@ -315,7 +339,8 @@ def cmdline_handler(scriptname, argv):
 
     if options.icommand:
         # User did "hy -i ..."
-        return run_icommand(options.icommand, spy=options.spy)
+        return run_icommand(options.icommand, spy=options.spy,
+                            output_fn=options.repl_output_fn)
 
     if options.args:
         if options.args[0] == "-":
@@ -332,7 +357,7 @@ def cmdline_handler(scriptname, argv):
                 sys.exit(e.errno)
 
     # User did NOTHING!
-    return run_repl(spy=options.spy)
+    return run_repl(spy=options.spy, output_fn=options.repl_output_fn)
 
 
 # entry point for cmd line script "hy"

hy/importer.py

@@ -111,7 +111,7 @@ def import_buffer_to_module(module_name, buf):
     return mod
 
 
-def hy_eval(hytree, namespace, module_name):
+def hy_eval(hytree, namespace, module_name, ast_callback=None):
     foo = HyObject()
     foo.start_line = 0
     foo.end_line = 0
@@ -133,6 +133,9 @@ def hy_eval(hytree, namespace, module_name):
         node.lineno = 1
         node.col_offset = 1
 
+    if ast_callback:
+        ast_callback(_ast, expr)
+
     if not isinstance(namespace, dict):
         raise HyTypeError(foo, "Globals must be a dictionary")
 

tests/test_bin.py

@@ -23,12 +23,17 @@
 # DEALINGS IN THE SOFTWARE.
 import os
 import subprocess
+import re
 from hy._compat import PY3
 
 
 hy_dir = os.environ.get('HY_DIR', '')
 
 
+def hr(s=""):
+    return "hy --repl-output-fn=hy.contrib.hy-repr.hy-repr " + s
+
+
 def run_cmd(cmd, stdin_data=None, expect=0):
     p = subprocess.Popen(os.path.join(hy_dir, cmd),
                          stdin=subprocess.PIPE,
@@ -58,6 +63,61 @@ def test_bin_hy_stdin():
     output, _ = run_cmd("hy", '(koan)')
     assert "monk" in output
 
+    output, _ = run_cmd("hy --spy", '(koan)')
+    assert "monk" in output
+    assert "\\n  Ummon" in output
+
+    # --spy should work even when an exception is thrown
+    output, _ = run_cmd("hy --spy", '(foof)')
+    assert "foof()" in output
+
+
+def test_bin_hy_stdin_multiline():
+    output, _ = run_cmd("hy", '(+ "a" "b"\n"c" "d")')
+    assert "'abcd'" in output
+
+
+def test_bin_hy_stdin_comments():
+    _, err_empty = run_cmd("hy", '')
+
+    output, err = run_cmd("hy", '(+ "a" "b") ; "c"')
+    assert "'ab'" in output
+    assert err == err_empty
+
+    _, err = run_cmd("hy", '; 1')
+    assert err == err_empty
+
+
+def test_bin_hy_stdin_assignment():
+    # If the last form is an assignment, don't print the value.
+
+    output, _ = run_cmd("hy", '(setv x (+ "A" "Z"))')
+    assert "AZ" not in output
+
+    output, _ = run_cmd("hy", '(setv x (+ "A" "Z")) (+ "B" "Y")')
+    assert "AZ" not in output
+    assert "BY" in output
+
+    output, _ = run_cmd("hy", '(+ "B" "Y") (setv x (+ "A" "Z"))')
+    assert "AZ" not in output
+    assert "BY" not in output
+
+
+def test_bin_hy_stdin_hy_repr():
+    output, _ = run_cmd("hy", '(+ [1] [2])')
+    assert "[1, 2]" in output.replace('L', '')
+
+    output, _ = run_cmd(hr(), '(+ [1] [2])')
+    assert "[1 2]" in output
+
+    output, _ = run_cmd(hr("--spy"), '(+ [1] [2])')
+    assert "[1]+[2]" in output.replace('L', '').replace(' ', '')
+    assert "[1 2]" in output
+
+    # --spy should work even when an exception is thrown
+    output, _ = run_cmd(hr("--spy"), '(+ [1] [2] (foof))')
+    assert "[1]+[2]" in output.replace('L', '').replace(' ', '')
+
 
 def test_bin_hy_cmd():
     output, _ = run_cmd("hy -c \"(koan)\"")