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diff ply-3.8/example/BASIC/basiclex.py @ 7267:343ff337a19b
<ais523> ` tar -xf ply-3.8.tar.gz
author | HackBot |
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date | Wed, 23 Mar 2016 02:40:16 +0000 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/ply-3.8/example/BASIC/basiclex.py Wed Mar 23 02:40:16 2016 +0000 @@ -0,0 +1,74 @@ +# An implementation of Dartmouth BASIC (1964) + +from ply import * + +keywords = ( + 'LET','READ','DATA','PRINT','GOTO','IF','THEN','FOR','NEXT','TO','STEP', + 'END','STOP','DEF','GOSUB','DIM','REM','RETURN','RUN','LIST','NEW', +) + +tokens = keywords + ( + 'EQUALS','PLUS','MINUS','TIMES','DIVIDE','POWER', + 'LPAREN','RPAREN','LT','LE','GT','GE','NE', + 'COMMA','SEMI', 'INTEGER','FLOAT', 'STRING', + 'ID','NEWLINE' +) + +t_ignore = ' \t' + +def t_REM(t): + r'REM .*' + return t + +def t_ID(t): + r'[A-Z][A-Z0-9]*' + if t.value in keywords: + t.type = t.value + return t + +t_EQUALS = r'=' +t_PLUS = r'\+' +t_MINUS = r'-' +t_TIMES = r'\*' +t_POWER = r'\^' +t_DIVIDE = r'/' +t_LPAREN = r'\(' +t_RPAREN = r'\)' +t_LT = r'<' +t_LE = r'<=' +t_GT = r'>' +t_GE = r'>=' +t_NE = r'<>' +t_COMMA = r'\,' +t_SEMI = r';' +t_INTEGER = r'\d+' +t_FLOAT = r'((\d*\.\d+)(E[\+-]?\d+)?|([1-9]\d*E[\+-]?\d+))' +t_STRING = r'\".*?\"' + +def t_NEWLINE(t): + r'\n' + t.lexer.lineno += 1 + return t + +def t_error(t): + print("Illegal character %s" % t.value[0]) + t.lexer.skip(1) + +lex.lex(debug=0) + + + + + + + + + + + + + + + + +