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# EXAMPLE #1

INPUT:

    123

BEFORE we call parse_int(…):

    123ABC
    ↑
    *a_pos

RETURN value from parse_int(…):

    true

After parse_int(…) returns:

    123
       ↑
       *a_pos refers to null terminator just after the integer literal.

    element.type  == ELEMENT_INT
    element.value == 123

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# EXAMPLE #2

INPUT:

    123ABC

BEFORE we call parse_int(…):

    123ABC
    ↑
    *a_pos

RETURN value from parse_int(…):

    true

After parse_int(…) returns:

    123ABC
       ↑
       *a_pos refers to the non-digit character after the integer literal.

    element.type  == ELEMENT_INT
    element.value == 123

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# EXAMPLE #3

INPUT:

    -A1

BEFORE we call parse_int(…):

    -A1
    ↑
    *a_pos

RETURN value from parse_int(…):

    false

After parse_int(…) returns:

    -A1
     ↑
     *a_pos refers first character that informed us this cannot be an integer literal.

    element.type  == (don't care)
    element.value == (don't care)