1 files changed, 75 insertions, 5 deletions
diff --git a/neb/std/fs.py b/neb/std/fs.py
index 495c7ea..d20cde9 100644
--- a/neb/std/fs.py
+++ b/neb/std/fs.py
@@ -2,9 +2,15 @@ from .. import TypeEnum, Environment, Arg, Builtin, evaluate, InterpretPanic
 from ..structs import *
 from pathlib import Path
 from glob import glob
+from io import UnsupportedOperation
+import sys
 
 FS = Environment()
 
+FS.register("_stdin_", Handle(sys.stdin))
+FS.register("_stdout_", Handle(sys.stdout))
+FS.register("_stderr_", Handle(sys.stderr))
+
 def interpretExists(symbol, args, env, ns):
     return Bool(Path(args[0].value).resolve().exists())
 
@@ -39,13 +45,77 @@ def interpretWithWrite(symbol, args, env, ns):
 FS.register("with-write", Builtin("with-write", interpretWithWrite, [Arg("filename", TypeEnum.STRING)], Arg("exprs", TypeEnum.ANY, lazy=True)))
 
 def interpretWrite(symbol, args, env, ns):
-    # write :string :filehandle
-    line = args[0]
+    string = args[0]
     handle = args[1]
-    handle.args[0].write(line.value)  # TODO wrong! how do we evaluate a handle?
-    return Literal([])
+    try:
+        handle.file.write(string.value)
+    except UnsupportedOperation:
+        raise InterpretPanic(symbol, f"{handle} is not writable!")
+    except ValueError:
+        raise InterpretPanic(symbol, f"{handle} is closed")
+    return List([])
+
+FS.register("write", Builtin("write", interpretWrite, [Arg("string", TypeEnum.STRING), Arg("handle", TypeEnum.HANDLE)], return_type=TypeEnum.LIST))
+
+def interpretOpenRead(symbol, args, env, ns):
+    name = args[0].value
+    fil = Path(name)
+    if not fil.exists():
+        raise InterpretPanic(symbol, "file does not exist", fil)
+    try:
+        f = open(str(fil), "r")
+    except:
+        raise InterpretPanic(symbol, "cannot open {fil} for reading")
+    return Handle(f)
+
+FS.register("open-read", Builtin("open-read", interpretOpenRead, [Arg("filename", TypeEnum.STRING)], return_type=TypeEnum.HANDLE))
+
+def interpretOpenWrite(symbol, args, env, ns):
+    name = args[0].value
+    fil = Path(name)
+    try:
+        f = open(str(fil), "w")
+    except:
+        raise InterpretPanic(symbol, "cannot open {fil} for writing")
+    return Handle(f)
+
+FS.register("open-write", Builtin("open-write", interpretOpenWrite, [Arg("filename", TypeEnum.STRING)], return_type=TypeEnum.HANDLE))
+
+def interpretOpenAppend(symbol, args, env, ns):
+    name = args[0].value
+    fil = Path(name)
+    try:
+        f = open(str(fil), "a")
+    except:
+        raise InterpretPanic(symbol, "cannot open {fil} for appending")
+    return Handle(f)
+
+FS.register("open-append", Builtin("open-append", interpretOpenAppend, [Arg("filename", TypeEnum.STRING)], return_type=TypeEnum.HANDLE))
+
+def interpretClose(symbol, args, env, ns):
+    try:
+        args[0].file.close()
+        # TODO ideally we'd be able to remove it from the env
+        # but by this point, we don't know its symbol
+        # though it may not be in the env, e.g.
+        # (close (print (read (open-read "fil.txt"))))
+    except:
+        raise InterpretPanic(symbol, "cannot close {args[0]}")
+    return List([])
+
+FS.register("close", Builtin("close", interpretClose, [Arg("handle", TypeEnum.HANDLE)], return_type=TypeEnum.LIST))
+
+def interpretRead(symbol, args, env, ns):
+    handle = args[0]
+    try:
+        inp = args[0].file.read()
+    except UnsupportedOperation:
+        raise InterpretPanic(symbol, f"{handle} is not writable!")
+    except ValueError:
+        raise InterpretPanic(symbol, f"{handle} is closed")
+    return String(inp)
 
-FS.register("write", Builtin("write", interpretWrite, [Arg("string", TypeEnum.STRING), Arg("filename", TypeEnum.LIST)]))
+FS.register("read", Builtin("read", interpretRead, [Arg("handle", TypeEnum.HANDLE)], return_type=TypeEnum.STRING))
 
 def interpretReadLines(symbol, args, env, ns):
     target_file_name = args[0].value