168 lines
4.0 KiB
Python
168 lines
4.0 KiB
Python
# ***************************************************************************
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# * Copyright (c) 2020 Werner Mayer <wmayer[at]users.sourceforge.net> *
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# * *
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# * This file is part of the FreeCAD CAx development system. *
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# * *
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# * This program is free software; you can redistribute it and/or modify *
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# * it under the terms of the GNU Lesser General Public License (LGPL) *
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# * as published by the Free Software Foundation; either version 2 of *
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# * the License, or (at your option) any later version. *
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# * for detail see the LICENCE text file. *
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# * *
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# * This program is distributed in the hope that it will be useful, *
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# * but WITHOUT ANY WARRANTY; without even the implied warranty of *
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# * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
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# * GNU Library General Public License for more details. *
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# * *
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# * You should have received a copy of the GNU Library General Public *
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# * License along with this program; if not, write to the Free Software *
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# * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 *
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# * USA *
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# * *
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# ***************************************************************************
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__title__ = "FEM Utilities"
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__author__ = "Werner Mayer"
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__url__ = "https://www.freecad.org"
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tokens = (
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"NAME",
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"FLOAT",
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"INT",
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"PLUS",
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"MINUS",
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"TIMES",
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"DIVIDE",
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"EQUALS",
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"LPAREN",
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"RPAREN",
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"POWER",
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)
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# Tokens
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t_PLUS = r"\+"
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t_MINUS = r"-"
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t_TIMES = r"\*"
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t_DIVIDE = r"/"
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t_EQUALS = r"="
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t_LPAREN = r"\("
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t_RPAREN = r"\)"
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t_POWER = r"\^"
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t_NAME = r"[a-zA-Z_][a-zA-Z0-9_]*"
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def t_FLOAT(t):
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r"\d+\.(\d+)?([eE][-+]?\d+)?"
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t.value = float(t.value)
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return t
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def t_INT(t):
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r"\d+"
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t.value = int(t.value)
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return t
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# Ignored characters
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t_ignore = " \t"
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def t_COMMENT(t):
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r"\#.*"
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pass
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def t_newline(t):
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r"\n+"
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t.lexer.lineno += t.value.count("\n")
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def t_error(t):
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print("Illegal character '%s'" % t.value[0])
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t.lexer.skip(1)
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# Build the lexer
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import ply.lex as lex
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lex.lex()
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# Precedence rules for the arithmetic operators
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precedence = (
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("left", "PLUS", "MINUS"),
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("left", "TIMES", "DIVIDE"),
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("left", "POWER"),
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("right", "UMINUS"),
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)
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# dictionary of names (for storing variables)
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names = {}
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def p_statement_assign(p):
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"statement : NAME EQUALS expression"
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names[p[1]] = p[3]
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def p_statement_expr(p):
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"statement : expression"
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print(p[1])
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def p_expression_binop(p):
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"""expression : expression PLUS expression
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| expression MINUS expression
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| expression TIMES expression
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| expression DIVIDE expression
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| expression POWER expression"""
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if p[2] == "+":
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p[0] = p[1] + p[3]
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elif p[2] == "-":
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p[0] = p[1] - p[3]
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elif p[2] == "*":
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p[0] = p[1] * p[3]
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elif p[2] == "/":
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p[0] = p[1] / p[3]
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elif p[2] == "^":
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p[0] = p[1] ** p[3]
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def p_expression_uminus(p):
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"expression : MINUS expression %prec UMINUS"
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p[0] = -p[2]
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def p_expression_group(p):
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"expression : LPAREN expression RPAREN"
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p[0] = p[2]
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def p_expression_float(p):
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"expression : FLOAT"
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p[0] = p[1]
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def p_expression_int(p):
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"expression : INT"
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p[0] = p[1]
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def p_expression_name(p):
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"expression : NAME"
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try:
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p[0] = names[p[1]]
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except LookupError:
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print("Undefined name '%s'" % p[1])
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p[0] = 0
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def p_error(p):
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print("Syntax error at '%s'" % p.value)
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import ply.yacc as yacc
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yacc.yacc(debug=False, write_tables=False)
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