homework2

執行 python3 hw2.py

#語法:

冪次運算：輸入num^num 例：2^2

calc > 2^2
LexToken(NUMBER,2,1,0)
LexToken(POWER,'^',1,1)
LexToken(NUMBER,2,1,2)
4

根號運算：輸入num ** num 例：4 ** 2

calc > 4**2
LexToken(NUMBER,4,1,0)
LexToken(ROOT,'**',1,1)
LexToken(NUMBER,2,1,3)
2.0

for-loop運算: 輸入 for 變數 loop 起始值 終值 add ->執行連續加法運算

calc > for i loop 1 10 add
LexToken(FOR,'for',1,0)
LexToken(NAME,'i',1,4)
LexToken(LOOP,'loop',1,6)
LexToken(NUMBER,1,1,11)
LexToken(NUMBER,10,1,13)
LexToken(ADD,'add',1,16)

calc > i
LexToken(NAME,'i',1,0)
55

for-loop運算: 輸入 for 變數 loop 起始值 終值 avg ->執行連續加法平均運算

calc > for i loop 1 10 avg
LexToken(FOR,'for',1,0)
LexToken(NAME,'i',1,4)
LexToken(LOOP,'loop',1,6)
LexToken(NUMBER,1,1,11)
LexToken(NUMBER,10,1,13)
LexToken(AVG,'avg',1,16)

calc > i
LexToken(NAME,'i',1,0)
5.5

if-else運算: if 變數 符號(>,>=,==,<=,<) 變數=數值 else 變數=數值 :

calc > i=10
LexToken(NAME,'i',1,0)
LexToken(EQUALS,'=',1,1)
LexToken(NUMBER,10,1,2)

calc > if i==10 k=5 else k=3:
LexToken(IF,'if',1,0)
LexToken(NAME,'i',1,3)
LexToken(EQUAL,'==',1,4)
LexToken(NUMBER,10,1,6)
LexToken(NAME,'k',1,9)
LexToken(EQUALS,'=',1,10)
LexToken(NUMBER,5,1,11)
LexToken(ELSE,'else',1,13)
LexToken(NAME,'k',1,18)
LexToken(EQUALS,'=',1,19)
LexToken(NUMBER,3,1,20)
LexToken(COLON,':',1,21)

calc > k
LexToken(NAME,'k',1,0)
5

繪製passing tree，例:1+2+3+4

calc > 1+2+3+4
LexToken(NUMBER,1,1,0)
LexToken(PLUS,'+',1,1)
LexToken(NUMBER,2,1,2)
LexToken(PLUS,'+',1,3)
LexToken(NUMBER,3,1,4)
LexToken(PLUS,'+',1,5)
LexToken(NUMBER,4,1,6)
10

在資料夾內可找到nx_test.png所畫出的結果

參考資料 :

1.https://www.dabeaz.com/ply/ply.html
2.https://stackoverflow.com/questions/47746590/python-ply-issue-with-if-else-and-while-statements