equal
deleted
inserted
replaced
799 By using the records and extracting the environment, the |
799 By using the records and extracting the environment, the |
800 result is the following list: |
800 result is the following list: |
801 |
801 |
802 \begin{center}\tt |
802 \begin{center}\tt |
803 \begin{tabular}{l} |
803 \begin{tabular}{l} |
804 KEYWORD(if),\\ |
804 (k, if),\\ |
805 WHITESPACE,\\ |
805 (w, " "),\\ |
806 IDENT(true),\\ |
806 (i, true),\\ |
807 WHITESPACE,\\ |
807 (w, " "),\\ |
808 KEYWORD(then),\\ |
808 (k, then),\\ |
809 WHITESPACE,\\ |
809 (w, " "),\\ |
810 KEYWORD(then),\\ |
810 (k, then),\\ |
811 WHITESPACE,\\ |
811 (w, " "),\\ |
812 NUM(42),\\ |
812 (n, 42),\\ |
813 WHITESPACE,\\ |
813 (w, " "),\\ |
814 KEYWORD(else),\\ |
814 (k, else),\\ |
815 WHITESPACE,\\ |
815 (w, " "),\\ |
816 OP(+) |
816 (o, +) |
817 \end{tabular} |
817 \end{tabular} |
818 \end{center} |
818 \end{center} |
819 |
819 |
820 \noindent Typically we are not interested in the whitespaces |
820 \noindent Typically we are not interested in the whitespaces |
821 and comments and would filter them out: this gives |
821 and comments and would filter them out: this gives |
822 |
822 |
823 \begin{center}\tt |
823 \begin{center}\tt |
824 \begin{tabular}{l} |
824 \begin{tabular}{l} |
825 KEYWORD(if),\\ |
825 (k, if),\\ |
826 IDENT(true),\\ |
826 (i, true),\\ |
827 KEYWORD(then),\\ |
827 (k, then),\\ |
828 KEYWORD(then),\\ |
828 (k, then),\\ |
829 NUM(42),\\ |
829 (n, 42),\\ |
830 KEYWORD(else),\\ |
830 (k, else),\\ |
831 OP(+) |
831 (o, +) |
832 \end{tabular} |
832 \end{tabular} |
833 \end{center} |
833 \end{center} |
834 |
834 |
835 \noindent |
835 \noindent |
836 which will be the input for the next phase of our compiler. |
836 which will be the input for the next phase of our compiler. |