Analysis of A highly valuable chain of thoughts

HAD cigarettes no ashes,
And roses ne'er a thorn,
No man would be a funker
Of whin, or burn, or bunker.
There were no need for mashies,
The turf would ne'er be torn,
Had cigarettes no ashes,
And roses ne'er a thorn.

Had cigarettes no ashes,
And roses ne'er a thorn,
The big trout would not ever
Escape into the river.
No gut the salmon smashes
Would leave us all forlorn,
Had cigarettes no ashes,
And roses ne'er a thorn.

But 'tis an unideal
Sad world in which we're born,
And things will 'go contrairy'
With Martin and with Mary:
And every day the real
Comes bleakly in with morn,
And cigarettes have ashes,
And every rose a thorn.