interpreter | 易学教程

/usr/bin/perl: bad interpreter: Text file busy

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问题 This is a new one for me: What does this error indicate? /usr/bin/perl: bad interpreter: Text file busy There were a couple of disk-intensive processes running at the time, but I've never seen that message before—in fact, this is the first time that I can remember getting an error when trying to run a Perl script. After a few seconds of waiting, I was able to run it, and haven't seen the issue since, but it would be nice to have an explanation for this. Running Ubuntu 9.04, file system is

How to force interpreter show complete stack trace?

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问题 Is there any way to force Scala interpreter (started through SBT) to print complete stack trace. By default, less than 10 lines are displayed: scala> new CacheMonitoringClient javax.management.InstanceNotFoundException: com.bea:Name=DomainRuntimeService,Type=weblogic.management.beanservers.domainrun time.DomainRuntimeServiceMBean at weblogic.rjvm.ResponseImpl.unmarshalReturn(ResponseImpl.java:195) at weblogic.rmi.internal.BasicRemoteRef.invoke(BasicRemoteRef.java:224) at javax.management

CPython is bytecode interpreter?

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I don't really get the concept of "bytecode interpreter" in the context of CPython. Can someone shed some light over the whole picture? Does it mean that CPython will compile and execute pyc file (bytecode file?). Then what compile py file to pyc file? And how is Jython different from CPython (except they are implemented in different languages). I also read somewhere that Python is C++ interpretation. Is this correct? And what does that mean? I'm still very new to Python, so forgive me if I ask the dumb questions... Thank you so much! CPython is the implementation of Python in C. It's the

How to use third party libraries with Scala REPL?

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I've downloaded Algebird and I want to try out few things in the Scala interpreter using this library. How do I achieve this? Rüdiger Klaehn Of course, you can use scala -cp whatever and manually manage your dependencies. But that gets quite tedious, especially if you have multiple dependencies. A more flexible approach is to use sbt to manage your dependencies. Search for the library you want to use on search.maven.org . Algebird for example is available by simply searching for algebird . Then create a build.sbt referring to that library, enter the directory and enter sbt console . It will

How to get the current Python interpreter path from inside a Python script? [duplicate]

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问题 This question already has an answer here: Find full path of the Python interpreter? 3 answers I want to run a Python script from a Python script with subprocess , and I wish to do it using the same interpreter for each of them. I'm using virtualenv, so I'd like to do something like: subprocess.Popen('%s script.py' % python_bin) How do I get python_bin ? It should be /usr/bin/python outside a virtualenv, and /path/to/env/bin/python in a virtualenv. 回答1: The name of the interpreter is stored in

PyCharm. /usr/bin/python^M: bad interpreter [duplicate]

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问题 This question already has an answer here: ./configure : /bin/sh^M : bad interpreter [duplicate] 15 answers Cannot figure out, where to change EOF in PyCharm. My scripts, started with: #!/usr/bin/python # -*- coding: utf-8 -*- Outputs something like this, when I try to run it like executable (chmode +x): -bash: ./main.py: /usr/bin/python^M: bad interpreter: No such file or directory What to do and how to be? 回答1: Set line separator to Unix : 回答2: The issue is not EOF but EOL. The shell sees a

Does Python optimize away a variable that's only used as a return value?

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问题 Is there any ultimate difference between the following two code snippets? The first assigns a value to a variable in a function and then returns that variable. The second function just returns the value directly. Does Python turn them into equivalent bytecode? Is one of them faster? Case 1 : def func(): a = 42 return a Case 2 : def func(): return 42 回答1: No, it doesn't . The compilation to CPython byte code is only passed through a small peephole optimizer that is designed to do only basic

References Needed for Implementing an Interpreter in C/C++

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I find myself attached to a project to integerate an interpreter into an existing application. The language to be interpreted is a derivative of Lisp, with application-specific builtins. Individual 'programs' will be run batch-style in the application. I'm surprised that over the years I've written a couple of compilers, and several data-language translators/parsers, but I've never actually written an interpreter before. The prototype is pretty far along, implemented as a syntax tree walker, in C++. I can probably influence the architecture beyond the prototype, but not the implementation

How do I add tab completion to the Python shell?

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When starting a django application using python manage.py shell , I get an InteractiveConsole shell - I can use tab completion, etc. Python 2.5.1 (r251:54863, Apr 15 2008, 22:57:26) [GCC 4.0.1 (Apple Inc. build 5465)] on darwin Type "help", "copyright", "credits" or "license" for more information. (InteractiveConsole) When just starting a python interpreter using python , it doesn't offer tab completion. Can someone tell me what django is doing to give me an interactive console, or what I need to do to start an interactive console without a django app? ashchristopher I may have found a way to

Java Threads vs OS Threads

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问题 Looks like I have messed up with Java Threads/OS Threads and Interpreted language. Before I begin, I do understand that Green Threads are Java Threads where the threading is taken care of by the JVM and the entire Java process runs only as a single OS Thread. Thereby on a multi processor system it is useless. Now my questions is. I have two Threads A and B. Each with 100 thousand lines of independent code. I run these threads in my Java Program on a multiprocessor system. Each Thread will be