transpiler

During a reactJs session that I was attending, the presenter used a term transpiler for some code conversion/porting happening. I've always used and heard the terms compiler and interpreter when it comes to converting a language code to a runnable form on a computer system/machine. Transpiler is completely new to me. Can someone help me to understand how a Transpiler is different from a compiler or an interpreter and why it is really needed? As is mentioned in this Wiki article , it is a type of compiler which translates source code from one programming language to another programming language

In C / C++ languages one can use macros or as called "per-processor directives" to instruct the compiler how the code should be read. The simple commands of #def , #ifdef , #ifndef , #else , #endif ... give the compiler the ability to check for Operating system, compiler and other environment information. I know Octave and Scilab are interpreted languages, but I'm wondering if is there any way to tell the interpreter to replaces parts of script while loading it? For example can I write a code which is commented based on Scilab syntax // and then instruct the interpreter to read them as Octave

In this question that I asked here: Why does mutating a module update the reference if calling that module from another module, but not if calling from itself? I'm asking about the nature of module mutation. However as it it turns out, ES6 modules can't actually be mutated - all of their properties are treated as constants. ( See this answer ) But somehow - when Jest tests modules - they can be mutated, and that's how Jest allows for mocking. How is this happening? I imagine that it's a babel plugin that that's running - transpiling the module to CommonJS modules? Is there any documentation

Is there a software converter out there that can automatically convert this python code to PHP? #!/usr/bin/python import math def calcNumEntropyBits(s): if len(s) <= 0: return 0.0 symCount = {} for c in s: if c not in symCount: symCount[c] = 1 else: symCount[c] += 1 entropy = 0.0 for c,n in symCount.iteritems(): prob = n / float(len(s)) entropy += prob * (math.log(prob)/math.log(2)) if entropy >= 0.0: return 0.0 else: return -(entropy*len(s)) def testEntropy(s): print "Bits of entropy in '%s' is %.2f" % (s, calcNumEntropyBits(s)) testEntropy('hello world') testEntropy('bubba dubba')

I have a 4.2 rails app and am considering slowly converting the JS to ES6. Right now I'm using the standard rails manifest file from the asset pipeline to pre-process my js. I'm not sure how to go about starting to use ES6 (adding a transpile step) in my rails app. Is there a built-in method, or a recommended tool or workflow? At present unfortunately there isn't really a 'standard' way of doing this - a lot of it depends on the requirements of your app and if you are able to upgrade Sprockets and/or Rails. Option 1: Stay on Rails 4.2 and Sprockets 3, then use this gem to add ES6 support and