std/env

The environment as settings: .env files, and variables read as text, numbers, flags, and lists, with defaults and required ones, so that every missing or wrong variable is reported at once.

import "std/env"

load_env_file(".env")?
EnvReader r = env_reader()
str host = r.require_str("DATABASE_HOST")
int port = r.get_int("DATABASE_PORT", 5432)
bool debug = r.get_bool("DEBUG", false)
r.check()?      // DATABASE_HOST is missing; DEBUG is not true or false ('maybe')

Function or method	Result
`parse_env(text)`	the variables of `.env` text, in order, as a `map[str, str]`
`load_env_file(path)`, `load_env_file(path, override: true)`	sets the variables of a `.env` file, leaving those set already unless `override`, and gives how many it set
`env_reader()`	an `EnvReader`, whose methods read variables and keep the problems
`get_str(name, fallback)`, `require_str(name)`	the text of a variable; a required one must be set and not empty
`get_int(name, fallback)`, `require_int(name)`	a whole number
`get_float(name, fallback)`	a number
`get_bool(name, fallback)`	`true`, `yes`, `on`, or `1`, or `false`, `no`, `off`, or `0`, in any case
`get_list(name, separator)`	the trimmed items between separators, empty ones left out
`check()`	an `ERROR` of kind `"invalid_environment"` that lists every missing variable and every one not as wanted

A .env file has lines NAME=value, with export before them allowed and # comments. A value in single quotes is as it is; one in double quotes takes \n, \t, \", and \\, and may go on over several lines; and ${NAME} or $NAME in a value outside single quotes is the value of a variable before it or of the environment.