A couple of times I came across an expression "for to do something" appearing in contexts where just "to do sth" would be more suitable I think. Take for example a line from The Carter Family song Can the Circle Be Unbroken. It says:

I was standing by my window
On a cold and cloudy day
When I saw that hearse come a-rolling
For to carry my mother away

Ok I know that some rules do not apply in poetry but I'm positive I saw this 'structure' in other contexts too.
I failed to find it in my dictionaries so could someone please direct me to an online source on this topic or explain it to me? Is it archaic, informal, etc..

Thank you,
I went there for the purpose of (gerund)
I went there [for] (infinitive)

I think it's archaic, but it persists as a regional colloquialism and, as you note, in folk poetry:

Simple Simon went a-fishin'
For to catch a whale.
But all the water that he had
Was in his mother's pail.

We natives all learned this stuff as children.

Sorry, not clever enough to find a scholarly analysis. Nothing past 19th century.
Yes it's a common expression in old folk songs but it isn't used in modern English.
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Thanks a lot! I appreciate more your personal judgement as a native than a scholary analysis Emotion: smile
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Folk songs are really cute in their way of saying things. I seem to remember Dylan singing "...no other choice except but for to go" Emotion: smile
Could you elaborate on this one too? I mean, was it ever common to say that or is it just the folk style again? It appears to me that 'except' and 'but' are mutually exclusive in this context. What do you think of that?

While we're at it, take a look at another Dylan's line:

I don't mean trouble, please don't put me down or get upset,
I am not pleadin' or sayin', "I can't forget."
I do not walk the floor bowed down an' bent, but yet,
Mama, you been on my mind.

'But' next to 'yet' sounds off. I mean it sounds ok but I know it is off Emotion: big smile Right?
Don't use poetry or song lyrics to discover how modern prose works - they do all sorts of things to make the rhythm work and so on. Just enjoy it.

"no other choice but for to go" = "I had to go."