src.elv.sh@v0.21.0-dev.0.20240515223629-06979efb9a2a/pkg/eval/vars/env.go (about)

     1  package vars
     2  
     3  import (
     4  	"errors"
     5  	"os"
     6  )
     7  
     8  var errEnvMustBeString = errors.New("environment variable can only be set string values")
     9  
    10  type envVariable struct {
    11  	name string
    12  }
    13  
    14  func (ev envVariable) Set(val any) error {
    15  	if s, ok := val.(string); ok {
    16  		os.Setenv(ev.name, s)
    17  		return nil
    18  	}
    19  	return errEnvMustBeString
    20  }
    21  
    22  func (ev envVariable) Get() any {
    23  	return os.Getenv(ev.name)
    24  }
    25  
    26  func (ev envVariable) Unset() error {
    27  	return os.Unsetenv(ev.name)
    28  }
    29  
    30  func (ev envVariable) IsSet() bool {
    31  	_, ok := os.LookupEnv(ev.name)
    32  	return ok
    33  }
    34  
    35  // FromEnv returns a Var corresponding to the named environment variable.
    36  func FromEnv(name string) UnsettableVar {
    37  	return envVariable{name}
    38  }