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In recent years interactive data analysis and presentation packages have become more and more attractive on conventional timesharing systems. The advent of personal workstations with their good response time and powerful graphics capabilities is making these systems even more popular. PAW has been designed in that spirit. It combines the best features and the experience acquired with the existing systems together with the user friendliness now possible on modern workstations. Rather than being a monolithic system, which may be well suited to one operating system, PAW is built with modules which can also be used in the batch environment or by other interactive programs. PAW has been designed to work on many different configurations.

S t . d 8 t i d data ir premented on the distribution of FORTRAN identifiers as a function of length and initial character. The performance of two hash coding algorithms is tested with random probing on a pool of actual FORTRAN identifieis. A sigdilcant gain in performance b observed relative to the theoretical case of random keys, which reinforces the cue for h u h coding for symbol table construction in FORTRAN compilers. ~(gy worn Hash coding Symbol table FORTRAN compiler

A few remarks are given on the relations between syntax and semantics in the programming languages. The aim is to point out that, it is true that the grammar of a contex-free language should be conceived not only as a strings-generating device but also as a method for expressing a meaning, then the grammar of ALGOL is open to some criticism.

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