We do. \newcommand is \long by default; if you want un-long macros, you have to use \newcommand*.

A more philosophical answer: \long is one of the several error-catching mechanisms that Knuth built into TeX. Or rather, not using \long allows TeX to catch missing-brace errors where the argument of a macro would appear to span multiple paragraphs; that's where the "runaway argument" errors come from. So using \long by default means that you may use up TeX's memory before finding an error.

This is similar to my answer to this question about \outer, which has a similar purpose in buck-stopping out-of-control code. My conclusion there was that \outer reflects an obsolete prioritization of computer resources versus human resources, and I believe that I will make the same judgment of \long here. It appears that in both cases, the authors of LaTeX take this position as well.

We do. \newcommand is \long by default; if you want un-long macros, you have to use \newcommand*.

A more philosophical answer: \long is one of the several error-catching mechanisms that Knuth built into TeX. Or rather, not using \long allows TeX to catch missing-brace errors where the argument of a macro would appear to span multiple paragraphs; that's where the "runaway argument" errors come from. So using \long by default means that you may use up TeX's memory before finding an error.

This is similar to my answer to this question about \outer, which has a similar purpose in buck-stopping out-of-control code. My conclusion there was that \outer reflects an obsolete prioritization of computer resources versus human resources, and I believe that I will make the same judgment of \long here. It appears that in both cases, the authors of LaTeX take this position as well.

We do. \newcommand is \long by default; if you want un-long macros, you have to use \newcommand*

We do. \newcommand is \long by default; if you want un-long macros, you have to use \newcommand*.

A more philosophical answer: \long is one of the several error-catching mechanisms that Knuth built into TeX. Or rather, not using \long allows TeX to catch missing-brace errors where the argument of a macro would appear to span multiple paragraphs; that's where the "runaway argument" errors come from. So using \long by default means that you may use up TeX's memory before finding an error.

This is similar to my answer to this question about \outer, which has a similar purpose in buck-stopping out-of-control code. My conclusion there was that \outer reflects an obsolete prioritization of computer resources versus human resources, and I believe that I will make the same judgment of \long here. It appears that in both cases, the authors of LaTeX take this position as well.