2534	 Design and Implementation of a Diagnostic Compiler for PL I	 PL C is a compiler for a dialect for PL I. The design objective was to provide a maximum degree of diagnostic assistance in a batch processing environment. For the most part this assistance is implicit and is provided automatically by the compiler. The most remarkable characteristic of PL C is its perseverance-it completes translation of every program submitted and continues execution until a user-established error limit is reached. This requires that the compiler repair errors encountered during both translation and execution and the design of PL C is dominated by this consideration. PL C also introduces several explicit user-controlled facilities for program testing. To accommodate these extensions to PL I without abandoning compatibility with IBM compiler PL C permits pseudo comments -constructions whose contents can optionally be considered either source test or comment. In spite of the diagnostic effort PL C is a fast and efficient processor. It effectively demonstrates that compilers can provide better diagnostic assistance than is customarily offered even when a sophisticated source language is employed and that this assistance need not be prohibitively costly. compilers debugging PL I programming languages
