let add_import env filename =
{
globals = env.globals;
num_globals = env.num_globals;
locals = env.locals;
num_locals = env.num_locals;
sdepth = env.sdepth;
max_depth = env.max_depth;
errors = env.errors;
warnings = env.warnings;
unique_id = env.unique_id;
names = env.names;
varprops = env.varprops;
imported = filename:: env.imported;
templates = env.templates;
constants = env.constants;
}