I began teaching a friend programming just recently (we're using Python), and when we began discussing variable creation and the assignment operator, she asked why the value on the right is assigned to the name on the left, and not vice-versa.
I had not thought about it too much before, because it seemed natural to me, but she said that left-to-right seemed more natural to her, since that's how most of us read natural languages.
I thought about it, and concluded that it makes code much easier to read, since the names that are assigned to (which the programmer will need to reuse) are easily visible, aligned on the left.
aligned = 2
on = 'foo' + 'bar' + 'foobar'
the = 5.0 / 2
left = 2 + 5
As opposed to:
2 = aligned
'foo' + 'bar' + 'foobar' = on
5.0 / 2 = the
2 + 5 = right
# What were the names again...?
Now I wonder if there are other reasons as well for this standard. Is there a history behind it? Or is there some technical reason why this is a good option (I don't know much about compilers)? And are there any programming languages that assign to the right side?
Best Answer
Ditto @paxdiablo. The early programming languages were written by mathematicians--actually all of them were. In mathematics, by her own principle--reading left to right-- it makes sense in the way it works.
x = 2y - 4.
In mathematics, you would say this: Let x be equal to 2y -4.
Also, even in algebra you do this. When you solve an equation for a variable, you isolate the variable you are solving for to the left side. i.e. y = mx + b;
Furthermore, once an entire family of languages-- such as the C family-- has a certain syntax, it is more costly to change.