Hi!.
In this blog series we will see that will i be sucessful or not in my attempt to build a programming language, an interpreter, a parser, a compiler and a virtual machine. For any questions starting with 'why' the answer is always 'why not?' except theese:
- Why Python? Python lets you focus on problem rather than fighting with language itself.
- Why not Rust? Rust is causing hair loss while fighting against it.
- Why not C? It explodes many times in your hands. You lose your hands.
If code that i write is not idiomatic and tastefull for you please ignore it.
Lets get started.
class Interpreter:
def __init__(self):
pass
def run(self,code):
for xs in code:
self.eval(xs)
# This is our magic function. It evauates xs parameter
# according to its first element and calls appropriate
# member function and passes the parameter to that function.
# If xs is not a list then returns xs itself:
def eval(self,xs):
if isinstance(xs,list):
return self.__getattribute__(xs[0])(xs)
return xs
# Our first function (or opcode) is Print. If last item
# is a comma it doesn't print newline:
def Print(self,xs):
if len(xs)==1:
print()
return
l=len(xs)-1
for i,x in enumerate(xs[1:]):
e=self.eval(x)
if i<l-1:
print(e,end="")
else:
if e!=",":
print(e)
else:
print(e,end="")
# This is AST (Abstract Syntax Tree) generated by
# parser. Consisting of recursive lists
# (No, not lisp :P )
code=[
["Print","Hello World!","Sky is blue"],
["Print",1,","],
["Print",2,","],
["Print",3],
["Print","a"],
["Print","b"],
["Print"],
["Print","c"],
]
interpreter=Interpreter()
interpreter.run(code)
Output is:
Hello World!Sky is blue
1,2,3
a
b
c
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