Mixing name/value pair syntax

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Matt J
Matt J 2026-1-7，5:56
编辑： Matt J 2026-1-9，17:43
Ran in:
In a Matlab seminar a few years ago, I asked why function calls that mix old style and new style name/value pair syntax would only work in a certain order. Specifically, the old style pairs must come first in the argument list. When the order is reversed, an error is thrown as illustrated below.
testFunc('A',10, B=20)
A: 10 B: 20
testFunc(B=20, 'A',10)
Unsupported use of the '=' operator. To compare values for equality, use '=='. To pass name-value arguments using the name=value format, provide these arguments after all other inputs.
A MathWorker at the seminar told me that this was by design, but there was no time for him to elaborate. Can anyone think why this would have been a deliberate design choice?
function testFunc(opts)
arguments
opts.A=1;
opts.B=2;
end
disp(opts)
end
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Rik
Rik 2026-1-9，17:07
Ran in:
Isn't there a single parser that looks for syntax errors? Why would the naive approach of making the Name=Value syntax work the same as {:} cause any issues anywhere? And why there be a requirement for Name=Value to be last either way?
Only partially on topic: I think the monstrosity below shows how poorly I understand what is happening.
tryme(A=10)
A = "A"
B = 10
function tryme(A,B)
arguments
A=1;
B=2;
end
A
B
end
Matt J
Matt J 2026-1-9，17:38
编辑：Matt J 2026-1-9，17:43
I think the monstrosity below shows how poorly I understand what is happening.
Nothing monstrous there. As you noted earlier, the A=10 syntax gets converted to a comma-separated pair {"A",10} and so the call is equivalent to,
args={"A",10};
tryme(args{:})
I might have expected,
args = {'A',10}
so that's a little strange.

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