95 lines
2.9 KiB
Python
95 lines
2.9 KiB
Python
|
#!/usr/bin/env python3
|
||
|
|
"""
|
||
|
|
Ny parser MVP (Stage 1): Ny -> JSON v0
|
||
|
|
|
||
|
|
Grammar (subset):
|
||
|
|
program := [return] expr EOF
|
||
|
|
expr := term (('+'|'-') term)*
|
||
|
|
term := factor (('*'|'/') factor)*
|
||
|
|
factor := INT | STRING | '(' expr ')'
|
||
|
|
|
||
|
|
Outputs JSON v0 compatible with --ny-parser-pipe.
|
||
|
|
"""
|
||
|
|
import sys, re, json
|
||
|
|
|
||
|
|
class Tok:
|
||
|
|
def __init__(self, kind, val, pos):
|
||
|
|
self.kind, self.val, self.pos = kind, val, pos
|
||
|
|
|
||
|
|
def lex(s: str):
|
||
|
|
i=n=0; n=len(s); out=[]
|
||
|
|
while i<n:
|
||
|
|
c=s[i]
|
||
|
|
if c.isspace():
|
||
|
|
i+=1; continue
|
||
|
|
if c in '+-*/()':
|
||
|
|
out.append(Tok(c,c,i)); i+=1; continue
|
||
|
|
if c.isdigit():
|
||
|
|
j=i
|
||
|
|
while j<n and s[j].isdigit():
|
||
|
|
j+=1
|
||
|
|
out.append(Tok('INT', int(s[i:j]), i)); i=j; continue
|
||
|
|
if c=='"':
|
||
|
|
j=i+1; buf=[]
|
||
|
|
while j<n:
|
||
|
|
if s[j]=='\\' and j+1<n:
|
||
|
|
buf.append(s[j+1]); j+=2; continue
|
||
|
|
if s[j]=='"':
|
||
|
|
j+=1; break
|
||
|
|
buf.append(s[j]); j+=1
|
||
|
|
out.append(Tok('STR',''.join(buf), i)); i=j; continue
|
||
|
|
if s.startswith('return', i):
|
||
|
|
out.append(Tok('RETURN','return', i)); i+=6; continue
|
||
|
|
raise SyntaxError(f"lex: unexpected '{c}' at {i}")
|
||
|
|
out.append(Tok('EOF','',n))
|
||
|
|
return out
|
||
|
|
|
||
|
|
class P:
|
||
|
|
def __init__(self,toks): self.t=toks; self.i=0
|
||
|
|
def cur(self): return self.t[self.i]
|
||
|
|
def eat(self,k):
|
||
|
|
if self.cur().kind==k: self.i+=1; return True
|
||
|
|
return False
|
||
|
|
def expect(self,k):
|
||
|
|
if not self.eat(k): raise SyntaxError(f"expect {k} at {self.cur().pos}")
|
||
|
|
def factor(self):
|
||
|
|
tok=self.cur()
|
||
|
|
if self.eat('INT'): return {"type":"Int","value":tok.val}
|
||
|
|
if self.eat('STR'): return {"type":"Str","value":tok.val}
|
||
|
|
if self.eat('('):
|
||
|
|
e=self.expr(); self.expect(')'); return e
|
||
|
|
raise SyntaxError(f"factor at {tok.pos}")
|
||
|
|
def term(self):
|
||
|
|
lhs=self.factor()
|
||
|
|
while self.cur().kind in ('*','/'):
|
||
|
|
op=self.cur().kind; self.i+=1
|
||
|
|
rhs=self.factor()
|
||
|
|
lhs={"type":"Binary","op":op,"lhs":lhs,"rhs":rhs}
|
||
|
|
return lhs
|
||
|
|
def expr(self):
|
||
|
|
lhs=self.term()
|
||
|
|
while self.cur().kind in ('+','-'):
|
||
|
|
op=self.cur().kind; self.i+=1
|
||
|
|
rhs=self.term()
|
||
|
|
lhs={"type":"Binary","op":op,"lhs":lhs,"rhs":rhs}
|
||
|
|
return lhs
|
||
|
|
def program(self):
|
||
|
|
if self.eat('RETURN'):
|
||
|
|
e=self.expr()
|
||
|
|
else:
|
||
|
|
e=self.expr()
|
||
|
|
self.expect('EOF')
|
||
|
|
return {"version":0, "kind":"Program", "body":[{"type":"Return","expr":e}]}
|
||
|
|
|
||
|
|
def main():
|
||
|
|
if len(sys.argv)<2:
|
||
|
|
print("usage: ny_parser_mvp.py <file.nyash>", file=sys.stderr); sys.exit(1)
|
||
|
|
with open(sys.argv[1],'r',encoding='utf-8') as f:
|
||
|
|
src=f.read()
|
||
|
|
toks=lex(src)
|
||
|
|
prog=P(toks).program()
|
||
|
|
print(json.dumps(prog, ensure_ascii=False))
|
||
|
|
|
||
|
|
if __name__=='__main__':
|
||
|
|
main()
|