Pascal (programming Language) - Reception - Criticism

While very popular in the 1980s and early 1990s, implementations of Pascal which closely followed Wirth's initial definition of the language were widely criticized for being unsuitable for use outside of teaching. Brian Kernighan, who popularized the C language, outlined his most notable criticisms of Pascal as early as 1981, in his paper Why Pascal Is Not My Favorite Programming Language. The most serious problem, described in this article, seems that array sizes and string lengths were part of the type so it was not possible to write a function that would accept variable length arrays or even strings as parameters (like a sorting library, for instance). The author also criticized the unpredictable order of evaluation of boolean expressions, poor library support, lack of static variables and a number of smaller issues. Also, he stated that the language did not provide any simple constructs to "escape" (knowingly and forcibly ignore) restrictions and limitations. (However, there is a feature of "record variants" that does allow such an "escape," though it is decidedly cumbersome.) More general complaints from other sources noted that the scope of declarations were not clearly defined in the original language definition, which sometimes had serious consequences when using forward declarations to define pointer types, or when record declarations lead to mutual recursion, or when an identifier may or may not have been used in an enumeration list. Another difficulty was that, like ALGOL 60, the language did not allow procedures or functions passed as parameters to pre-define what their parameters are supposed to be.

On the other hand, many major development efforts in the 1980s, such as for the Apple Lisa and Macintosh, heavily depended on Pascal (to the point where the C interface for the Macintosh Toolbox had to use Pascal data types).