EULER: A Generalization ALGOL, and its Formal Definition: Part I* A method for defining programming languages is developed which introduces a rigorous relationship between structure and meaning. The structure of a language is defined by a phrase structure syntax, the meaning in terms of the effects which the execution of a sequence of interpretation rules exerts upon a fixed set of variables, called the Environment. There exists a one-to-one correspondence between syntactic rules and interpretation rules is determined by the sequence of corresponding syntactic reductions which constitute a parse. The individual interpretation rules are explained in terms of an elementary an d obvious algorithmic notation. A constructive method for evaluating a text is provided, and for certain decidable classes of languages their unambiguity is proved. As an example, a generalization of ALGOL is described in full detail to demonstrate that concepts like block-structure, procedures, parameters, etc. can be defined adequately and precisely by this method. CACM January, 1966 Wirth, N. Weber, H. CA660104 JB March 3, 1978 4:22 PM 249 4 1491 254 4 1491 272 4 1491 1037 4 1491 1086 4 1491 1102 4 1491 1109 4 1491 1132 4 1491 1140 4 1491 1188 4 1491 1234 4 1491 1234 4 1491 1263 4 1491 1265 4 1491 1270 4 1491 1306 4 1491 1323 4 1491 1358 4 1491 1358 4 1491 1379 4 1491 1380 4 1491 1453 4 1491 1464 4 1491 1464 4 1491 1469 4 1491 1484 4 1491 1486 4 1491 1491 4 1491 1491 4 1491 1491 4 1491 1491 4 1491 1491 4 1491 1498 4 1491 1613 4 1491 1614 4 1491 1767 4 1491 1781 4 1491 1781 4 1491 1781 4 1491 1781 4 1491 1787 4 1491 1825 4 1491 1860 4 1491 1949 4 1491 321 4 1491 2059 4 1491 2061 4 1491 2083 4 1491 2126 4 1491 2178 4 1491 2178 4 1491 2179 4 1491 2252 4 1491 2325 4 1491 2326 4 1491 2341 4 1491 2470 4 1491 2546 4 1491 435 4 1491 437 4 1491 463 4 1491 483 4 1491 491 4 1491 2645 4 1491 2652 4 1491 2684 4 1491 2684 4 1491 2732 4 1491 2842 4 1491 2929 4 1491 2934 4 1491 560 4 1491 583 4 1491 3044 4 1491 3069 4 1491 3073 4 1491 627 4 1491 631 4 1491 632 4 1491 642 4 1491 644 4 1491 653 4 1491 669 4 1491 679 4 1491 680 4 1491 691 4 1491 761 4 1491 761 4 1491 762 4 1491 763 4 1491 123 4 1491 140 4 1491 919 4 1491 949 4 1491 989 4 1491 989 4 1491 196 5 1491 1140 5 1491 1303 5 1491 1491 5 1491 1491 5 1491 1491 5 1491 1542 5 1491 1683 5 1491 1693 5 1491 1781 5 1491 1787 5 1491 1836 5 1491 1945 5 1491 2060 5 1491 2061 5 1491 2082 5 1491 2091 5 1491 2152 5 1491 2179 5 1491 2340 5 1491 2356 5 1491 2546 5 1491 2603 5 1491 2698 5 1491 2708 5 1491 2824 5 1491 2982 5 1491 2986 5 1491 3045 5 1491 3093 5 1491 3184 5 1491 729 5 1491 823 6 1491 123 6 1491 196 6 1491 196 6 1491 914 6 1491 915 6 1491 917 6 1491 919 6 1491 970 6 1491 984 6 1491 989 6 1491 990 6 1491 990 6 1491 1007 6 1491 1012 6 1491 1046 6 1491 1084 6 1491 1098 6 1491 1122 6 1491 1131 6 1491 1138 6 1491 1139 6 1491 1139 6 1491 1140 6 1491 1140 6 1491 1141 6 1491 1141 6 1491 1141 6 1491 1141 6 1491 1149 6 1491 1191 6 1491 1191 6 1491 1198 6 1491 1200 6 1491 1215 6 1491 1215 6 1491 1223 6 1491 1223 6 1491 1265 6 1491 1265 6 1491 1303 6 1491 1323 6 1491 1336 6 1491 1358 6 1491 1366 6 1491 1366 6 1491 1380 6 1491 1396 6 1491 1421 6 1491 1421 6 1491 1421 6 1491 1455 6 1491 1460 6 1491 1462 6 1491 1463 6 1491 1467 6 1491 1468 6 1491 1469 6 1491 1477 6 1491 1477 6 1491 1477 6 1491 1477 6 1491 1477 6 1491 1477 6 1491 1477 6 1491 1477 6 1491 1477 6 1491 1477 6 1491 1477 6 1491 1477 6 1491 1487 6 1491 1491 6 1491 1491 6 1491 1491 6 1491 1491 6 1491 1491 6 1491 1491 6 1491 1491 6 1491 1491 6 1491 1491 6 1491 1491 6 1491 1491 6 1491 1491 6 1491 1491 6 1491 1491 6 1491 1491 6 1491 1491 6 1491 1491 6 1491 1491 6 1491 1491 6 1491 1491 6 1491 1491 6 1491 1491 6 1491 1491 6 1491 1491 6 1491 1496 6 1491 1496 6 1491 1496 6 1491 1531 6 1491 1535 6 1491 1565 6 1491 1601 6 1491 1602 6 1491 1613 6 1491 1614 6 1491 1614 6 1491 1626 6 1491 1641 6 1491 1683 6 1491 1683 6 1491 1683 6 1491 1767 6 1491 1781 6 1491 1781 6 1491 1781 6 1491 1787 6 1491 1787 6 1491 1788 6 1491 205 6 1491 1825 6 1491 1825 6 1491 210 6 1491 1836 6 1491 1836 6 1491 1836 6 1491 224 6 1491 224 6 1491 249 6 1491 1869 6 1491 288 6 1491 316 6 1491 381 6 1491 398 6 1491 2015 6 1491 2110 6 1491 2110 6 1491 2110 6 1491 2111 6 1491 11 6 1491 2126 6 1491 2179 6 1491 2179 6 1491 2227 6 1491 2340 6 1491 2340 6 1491 2340 6 1491 2534 6 1491 2534 6 1491 2556 6 1491 2556 6 1491 2708 6 1491 404 6 1491 404 6 1491 410 6 1491 463 6 1491 464 6 1491 483 6 1491 483 6 1491 3184 6 1491 3184 6 1491 3184 6 1491 3188 6 1491 3198 6 1491 518 6 1491 577 6 1491 584 6 1491 584 6 1491 600 6 1491 669 6 1491 680 6 1491 680 6 1491 680 6 1491 680 6 1491 680 6 1491 691 6 1491 763 6 1491 763 6 1491 763 6 1491 763 6 1491 773 6 1491 799 6 1491 799 6 1491 799 6 1491