Aliases should not be dropped at the end of the scope

Currently, aliases are dropped at the end of the scope, and cannot be effectively defined in a for-loop or in an if statement. This is also true even if another script is sourced within the loop/if statement.

Ideally, aliases should act as export variables, and continue to be defined even after the end of the scope.

Importance

Suppose in the initrc file the user wants to iterate over all .ion scripts in another folder and source them all. This would capture all export variables, but will not save any aliases. Not only this behavior is inconvinient, it is also unclear.

Simple example

for _ in 0..1
    export TEST_VAR = "Var is defined"
    alias test_alias = echo "Alias is defined"
end

echo $TEST_VAR
test_alias

Would produce the following output (both ion script.ion and source script.ion):

Var is defined
ion: pipeline execution error: command not found: test_alias

Another example

Suppose with have two scripts: inner.ion

export TEST_VAR = "Var is defined"
alias test_alias = echo "Alias is defined"

and main.ion

if true
    source inner.ion
    echo "Test inside `if`"
    echo $TEST_VAR
    test_alias
end

echo -e "\nTest outside `if`"
echo $TEST_VAR
test_alias

Will produce the following output (both ion main.ion and source main.ion):

Test inside `if`
Var is defined
Alias is defined

Test outside `if`
Var is defined
ion: pipeline execution error: command not found: test_alias

Comparison with other shells

for _ in 0; do
    export TEST_VAR="Var is defined"
    alias test_alias="echo Alias is defined"
done

echo $TEST_VAR
test_alias

will have the following behaviour in other shells:

• Successful in sh,
• Successful in bash, but only if ran as source,
• Successful in zsh.