indent-sexpr

indent-sexpr.py

#!/usr/bin/env python3
import hy
import io

TAB = "  "

class Writer:
    indent: int = -1

    def __init__(self):
        self.indent = 0

    def visit(self, obj):
        if isinstance(obj, hy.models.Expression):
            s = self.visit_list(obj)
            s2 = self.visit_atom(obj)
            if len(s2) < 40:
                s = s2
            return s
        else:
            return self.visit_atom(obj)

    def visit_atom(self, obj):
        s = hy.repr(obj)
        s = s.replace('\t', ' ')
        s = s.replace('\n', ' ')
        for j in range(5):
            s = s.replace('  ', ' ')
        if s.startswith("'"):
            s = s[1:]
        return s

    def visit_list(self, ls):
        o = io.StringIO()
        self.on_indent(1)
        o.write("(")
        nhead = self.get_head(ls)
        for k, i in enumerate(ls):
            if k > 0:
                if k < nhead:
                    o.write(" ")
                else:
                    o.write(self.get_newline())
            s = self.visit(i)
            o.write(s)
        o.write(")")
        self.on_dedent(1)
        return o.getvalue()

    def get_head(self, ls):
        # TODO add special processing
        # for define, case, etc...
        return 2

    def get_newline(self):
        global TAB
        return "\n" + (TAB * self.indent)

    def on_indent(self, n=1):
        self.indent += n

    def on_dedent(self, n=1):
        self.indent -= n


if __name__ == '__main__':
    import sys
    writer = Writer()
    ins = "(list " + sys.stdin.read() + ")"
    ins = ins.replace("#t", "True")
    ins = ins.replace("#f", "False")
    obj = hy.read(ins)
    for k, i in enumerate(obj[1:]):
        if k > 0:
            print("")
        outs = writer.visit(i)
        outs = outs.replace("True", "#t")
        outs = outs.replace("False", "#f")
        print(outs)