Convert a "mixed-base" string to ASCII
Lex + C, 156 124 bytes
%{
p(b){putchar(strtol(yytext,0,b));}
%}
%option noyywrap
%%
0[01]{7} {p(2);}
[01].. {p(8);}
.. {p(16);}
%%
main(){yylex();}

Compile with:
lex mixed_base.l
cc -o mixed_base lex.yy.c