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Build your own dotenv parser

A `.env` file has no specification. Every implementation disagrees about quotes, escapes, interpolation and where a value ends — so parsing one is a real parser exercise with no grammar to copy, only behaviour to pin down and defend.

what you end up with
RuntimeEnv — a dotenv parser that documents its own dialect

stages
21
estimated
15–25 h
level
Intermediate
track
Backend Engineering
language
Go
  • lines, comments and the `export ` prefix
  • single quotes are literal, double quotes are not
  • escapes, and the ones that only exist in one dialect
  • multi-line values
  • ${VAR} interpolation, with :- defaults
  • a `$` that is not a variable
  • a `#` inside a quoted value
  • CRLF, and a UTF-8 BOM on line one
  • precedence between the process environment and the file
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