In that video mentions regularity around minute 51. I have seen him using that term in person too.
The blog post you mentioned is misinformed. YACC does not parse all context-free grammars. It generates LALR parsers, that parse a strict subset of context-free languages (called deterministic context free languages). Not parseable with YACC does not imply not context free.
It is important to distinguish the programming language and its syntax. In most real compilers, the parser accepts a superset of the programming language and then other components of the compiler restrict it with semantic rules like type checking. What I am talking about here is the syntax only. In that sense, things like C, Java, and C# are most definitely context-free. The language specification usually comes with a context-free grammar describing the syntax. Whether you can use it to parse programs efficiently (in O(n)) and meaningfully is another matter.
The blog post you mentioned is misinformed. YACC does not parse all context-free grammars. It generates LALR parsers, that parse a strict subset of context-free languages (called deterministic context free languages). Not parseable with YACC does not imply not context free.
It is important to distinguish the programming language and its syntax. In most real compilers, the parser accepts a superset of the programming language and then other components of the compiler restrict it with semantic rules like type checking. What I am talking about here is the syntax only. In that sense, things like C, Java, and C# are most definitely context-free. The language specification usually comes with a context-free grammar describing the syntax. Whether you can use it to parse programs efficiently (in O(n)) and meaningfully is another matter.