Avoid using the past to discuss the future

Just noticed a sneaky little note at the end of this PMEG page. Thought I’d bring it up!

Now keep in mind that the simple past, present, and future tenses in Esperanto (words ending in -is,-as,-os respectively) actually do quite a bit of work. For example, past tense legis from legi "to read" can mean any of the following depending on context:

• read (past tense)
• was reading
• have read
• have been reading
• had read
• had been reading

Most commonly it will either be “read” or “was reading”, and maybe helper words will stress the other meanings. E.g. jam literally meaning “already”:

ĉu vi jam legis tiun libron?
have you (already) read that book?

The note on that PMEG page explains what you do in Esperanto when talking about having done something in the future. In English we might say:

I will hunt the badger as soon as I have read this book

“I will hunt” is simple future tense. But look at the weirdness we’re doing with the “read” verb. “I have read” is the perfect tense! It describes an already completed action/state! This is a bit odd, since we wouldn’t use “as soon as” if the action was already complete! I should already be hunting the badger if the reading was done!

Fear not, Esperanto makes sense. You’ve got two options. The first and most simple is to use the simple future tense:

Mi ĉasos la melon tuj kiam mi legos ĉi tiun libron

Notice legos is just the simple future tense "will read" (not the superfun building blocks). Since all it’s doing is describing a future event!

Your second option, is to be deadly precise using participles (see my series on the things):

Mi ĉasos la melon tuj kiam mi estos leginta ĉi tiun libron

mi estos leginta is literally “I will be having-read” (estos is future tense of esti “to be”), corresponding to “will have read” (=at some point in the future the reading will be completed), in the more clunky English rendering:

I will hunt the badger as soon as I will have read this book