adjust the project structure

.gitignore

@@ -1,2 +1,3 @@
 .vscode
 __pycache__
+myvenv

README.md

@@ -0,0 +1,20 @@
+## Scheme 解释器
+
+一个用Python完成的Scheme解释器。
+
+### 使用
+
+打开交互式解释器：
+
+    $ python run.py
+
+或运行Scheme文件：
+
+    $ python run.py test.scm
+
+### 代码功能
+
+`scm`目录下为SCIP中解释器的实例程序。
+
+`scmpy`为用Python完成的Scheme解释器，`run.py`为程序的入口。
+

py/run.py → run.py

@@ -7,26 +7,7 @@
 import os
 import sys
 
-from data import *
-from parse import InPort, parse
-from evaluater import evaluate
-
-def to_string(x):
-    """Convert a Python object back into a Lisp-readable string."""
-    if x is True:
-        return "#t"
-    elif x is False:
-        return "#f"
-    elif isinstance(x, Symbol):
-        return x
-    elif isinstance(x, Strings):
-        return '"%s"' % x
-    elif isinstance(x, List):
-        return '('+' '.join(map(to_string, x))+')'
-    elif isinstance(x, complex):
-        return str(x).replace('j', 'i')
-    else:
-        return str(x)
+from scmpy import InPort, parse, represent, evaluate
 
 def repl(prompt=None, inport=InPort(sys.stdin), out=sys.stdout):
     """A prompt-read-eval-print loop."""
@@ -36,11 +17,9 @@ def repl(prompt=None, inport=InPort(sys.stdin), out=sys.stdout):
                 #sys.stderr.write(prompt)
                 print(prompt, end='', flush=True)
             exp = parse(inport)
-            if exp is eof_object:
-                return
             val = evaluate(exp)
             if val is not None and out:
-                print(to_string(val), file=out)
+                print(represent(val), file=out)
         except Exception as e:
             print('%s: %s' % (type(e).__name__, e))
 
@@ -50,7 +29,7 @@ def load(filename):
 
 def interpreter(prompt='Lispy> '):
     """Interactive interpreted lisp program."""
-    sys.stderr.write("Lispy version 2.0\n")
+    sys.stderr.write("Scmpy version 2.0\n")
     repl(prompt=prompt)
 
 def interpret(filename):

scmpy/__init__.py

@@ -0,0 +1,4 @@
+from scmpy.parse import InPort, represent, parse
+from scmpy.evaluater import evaluate
+
+__all__ = ['InPort', 'represent', 'parse', 'evaluate']

py/data.py → scmpy/data.py

@@ -26,7 +26,7 @@ def Sym(s, symbol_table={}):
 quasiquote_, unquote_, unquotesplicing_ = \
     map(Sym, "quasiquote unquote unquote-splicing".split())
 
-class Number():
+class number():
     def __init__(self, value):
         if '.' in value:
             self.value = float(value)

py/evaluater.py → scmpy/evaluater.py

@@ -2,8 +2,8 @@
 Evaluate the expression.
 """
 
-from data import *
-from environment import Env, global_env
+from scmpy.data import *
+from scmpy.environment import Env, global_env
 
 def cond_to_if(expr):
     """"Convert the cond structure to an if construct."""

py/parse.py → scmpy/parse.py

@@ -3,8 +3,9 @@
 """
 
 import re
+import io
 
-from data import *
+from scmpy.data import *
 
 class InPort(object):
     """An input port. Retains a line of chars.
@@ -28,7 +29,10 @@ class InPort(object):
         ''', re.VERBOSE)
 
     def __init__(self, file):
-        self.file = file
+        if isinstance(file, str):
+            self.file = io.StringIO(file)
+        else:
+            self.file = file
         self.line = ''
 
     def next_token(self):
@@ -70,6 +74,23 @@ def atom(token):
 
 quotes = {"'":quote_, "`":quasiquote_, ",":unquote_, ",@":unquotesplicing_}
 
+def represent(x):
+    """Convert a Python object back into a Lisp-readable string."""
+    if x is True:
+        return "#t"
+    elif x is False:
+        return "#f"
+    elif isinstance(x, Symbol):
+        return x
+    elif isinstance(x, Strings):
+        return '"%s"' % x
+    elif isinstance(x, List):
+        return '('+' '.join(map(represent, x))+')'
+    elif isinstance(x, complex):
+        return str(x).replace('j', 'i')
+    else:
+        return str(x)
+
 def parse(inport):
     """Read a Scheme expression from an input port and parse it."""
     def read_ahead(token):
@@ -92,4 +113,4 @@ def read_ahead(token):
             return atom(token)
     # body of read
     token1 = inport.next_token()
-    return eof_object if token1 is eof_object else read_ahead(token1)
+    return read_ahead(token1)