Is the language of rectangular matrices in MATLAB-style syntax context free?
Delete all numbers from your language $L$, and replace $,$ with $a$ and $;$ as $b$.  Then intersect it with the regular language $a^*ba^*ba^*$.  You obtain a new language $L' = \{a^n b a^n b a^n : n \in \mathbb{N}\}$.  If $L$ is context-free, then $L'$ will be context-free too, as it has been obtained by applying a homomorphism and then intersecting with a regular language, both of which preserve context-freeness.  However, $L'$ is a standard example of a non-context-free language, so $L$ must be non-context-free as well.