[Question]
  [
[![](https://i.stack.imgur.com/BN6hG.png "colors.rgb(\"blue\") yields \"#0000FF\". colors.rgb(\"yellowish blue\") yields NaN. colors.sort() yields \"rainbow\"")](https://xkcd.com/1537/)
> 
> colors.rgb("blue") yields "#0000FF". colors.rgb("yellowish blue") yields NaN. colors.sort() yields "rainbow"
> 
> 
> 
Using the rules set out in the image and its title text (quoted here), create a program that accepts all the given input and displays the appropriate output.
* Input can be taken with stdin or nearest equivalent. There should be a line like `[n]>` on which to type it, and `n` increases by 1 each command. It should start at 1.
* The result should be displayed using stdout or nearest equivalent. There should be a `=>` on each line of output.
All 13 conditions, plus the 3 in the title (quoted) must work.
This is code golf, so shortest answer wins.
  
[Answer]
# Python 3, 700 698 697 689 683 639 611
Tabs as indentation.
```
from ast import*
E=literal_eval
O='=>%s\n'
P=print
I=int
def Q(a):P(O%a)
def W(a):Q('"%s"'%str(a))
def gb(a):W(_ if'y'in a else'#0000FF')
def t():W('rainbow')
def FLOOR(n):P(O%'|'*3+(O%'|{:_^10}').format(n))
def RANGE(*a):Q([('"','!',' ','!','"'),(1,4,3,4,5)][len(a)])
c=0
while 1:
    try:
        c+=1;A,*B=input('[%d]>'%c).split('+')
        if not A:W(c+I(B[0]))
        elif A=='""':Q("'\"+\"'")
        elif B:
            A=E(A);B=E(B[0])
            if A==B:Q('DONE')
            elif type(A)==list:Q(A[-1]==B-1)
            elif type(B)==list:W([I(A)])
            else:W(A+I(B))
        else:eval(A.lstrip('colrs.'))
    except:Q('Na'+['N','P','N.%s13'%('0'*13)][('-'in A)+len(B)])
```
*Since this uses a bare Except you can't Ctrl-C it. Ctrl-Z and kill %% work though*
Some of the conditions are generalized and others will only work with exact input.
1. `A+"B"` will work with any A and B not just when `A == B`
2. `"A"+[]` will work for any A that can be converted to an int (Includes hex and binary strings e.g 0xff and 0b01010)
3. `(A/0)` will work for any A, Eval Causes `DivideByZeroError` which is handled in the except
4. `(A/0)+B` will work with any A or B. `literal_eval` (E) raises an error.
5. `""+""` only works for the + sign. Anything else will print NaN, NaP or NaN.00...
6. `[A, B, C]+D` works by checking that `D == C+1` so will work for any length of list and any numbers.
7. ^^
8. `2/(2-(3/2+1/2))`, Anything that fails to parse that has `-` with a `+` somewhere after it will output NaN.000...13
9. `RANGE(" ")` Hardcoded
10. `+A` will work for any A. Ouputs `"current_line_number+A"`
11. `A+A` works for any A as long as they are the same and are bulitin python types
12. `RANGE(1,5)` Hardcoded.
13. `FLOOR(A)` works for any A.
14. `colors.rgb("blue")` The lstrip in eval turns this in `gb("blue")` which has a hardcoded response.
15. `colors.rgb("yellowish blue")` The lstrip in eval turns this in `gb("yellowish blue")` which attempts to use a non existent variable if `y` is present in the arguement causing an error which the except turns into NaN
16. `colors.sort()` The lstrip turns this into `t()` which has a hardcoded response.
![](https://i.stack.imgur.com/eq4Zp.png)
![](https://i.stack.imgur.com/c3Vk8.png)
*Brainsteel pointed out an error in my assumption for rule 10.*
![](https://i.stack.imgur.com/eSW72.png)
[Answer]
# Python, 1110 bytes
Operator overloading isn't evil, right??
```
from re import*
class V(str):
 def __add__(s,r):return s[:-1]+chr(ord(s[-1])+r)
class S(str):
 def __str__(s):return "'"+s+"'"if '"'in s else'"'+s+'"'
 def __repr__(s):return str(s)
 def __add__(s,r):s=str(s)[1:-1];return S('['+s+']'if type(r)==L else '"+"' if(s,r)==('','')else s+r)
class I(int):
 def __add__(s,r):return type(r)(int(s)+int(r))if s!=r else V('DONE')
 def __div__(s,r):return N if r==0 else int(s)/int(r)
 def __pos__(s):return s+c*10
 def __mul__(s,r):return V('NaN.'+'0'*13+'13')if r==1 else int(s)*int(r)
class L(list):
 def __add__(s,r):return V(str(r==s[-1]+1).upper())
def RANGE(a,b=0):return 2*(a,S(chr(ord(a)+1)))if b==0 else tuple([a]+[b-1,a+2]*((b-a)/4)+[b-1,b])
def FLOOR(n):return V('|\n|\n|\n|___%s___'%n)
def colorsrgb(c):
 m={'blue':V('#0000FF')}
 return m.get(c,N)
def colorssort():return V('rainbow')
N=V('NaN')
c=1
while True:
 try:l=raw_input('[%d] >'%c)
 except:break
 l=sub(r'(?<!"|\.)(\d+)(?!\.|\d)',r'I(\1)',l)
 l=sub(r'"(.*?)"',r'S("\1")',l)
 l=sub(r'\[(.*?)\]',r'L([\1])',l)
 l=sub(r'/\(','*(',l)
 l=sub('s\.','s',l)
 for x in str(eval(l)).split('\n'):print ' =',x
 c+=1
```
My goal wasn't as much winning (obviously) as it is making it as generic as possible. Very little is hardcoded. Try stuff like `RANGE(10)`, `9*1`, and `RANGE("A")`, `(2/0)+14`, and `"123"` for fun results!
Here's a sample session:
```
ryan@DevPC-LX:~/golf/xktp$ python xktp.py
[1] >ryan@DevPC-LX:~/golf/xktp$ python xktp.py
[1] >1+1
 = DONE
[2] >2+"2"
 = "4"
[3] >"2"+2
Traceback (most recent call last):
  File "xktp.py", line 31, in <module>
    for x in str(eval(l)).split('\n'):print ' =',x
  File "<string>", line 1, in <module>
  File "xktp.py", line 7, in __add__
    def __add__(s,r):s=str(s)[1:-1];return S('['+s+']'if type(r)==L else '"+"' if(s,r)==('','')else s+r)
TypeError: cannot concatenate 'str' and 'I' objects
ryan@DevPC-LX:~/golf/xktp$ python xktp.py
[1] >ryan@DevPC-LX:~/golf/xktp$
ryan@DevPC-LX:~/golf/xktp$
ryan@DevPC-LX:~/golf/xktp$
ryan@DevPC-LX:~/golf/xktp$ python xktp.py
[1] >2+"2"
 = "4"
[2] >"2"+[]
 = "[2]"
[3] >"2"+[1, 2, 3]
 = "[2]"
[4] >(2/0)
 = NaN
[5] >(2/0)+2
 = NaP
[6] >(2/0)+14
 = Na\
[7] >""+""
 = '"+"'
[8] >[1,2,3]+2
 = FALSE
[9] >[1,2,3]+4
 = TRUE
[10] >[1,2,3,4,5,6,7]+9
 = FALSE
[11] >[1,2,3,4,5,6,7]+8
 = TRUE
[12] >2/(2-(3/2+1/2))
 = NaN.000000000000013
[13] >9*1
 = NaN.000000000000013
[14] >RANGE(" ")
 = (" ", "!", " ", "!")
[15] >RANGE("2")
 = ("2", "3", "2", "3")
[16] >RANGE(2)
Traceback (most recent call last):
  File "xktp.py", line 31, in <module>
    for x in str(eval(l)).split('\n'):print ' =',x
  File "<string>", line 1, in <module>
  File "xktp.py", line 15, in RANGE
    def RANGE(a,b=0):return 2*(a,S(chr(ord(a)+1)))if b==0 else tuple([a]+[b-1,a+2]*((b-a)/4)+[b-1,b])
TypeError: ord() expected string of length 1, but I found
ryan@DevPC-LX:~/golf/xktp$ python xktp.py
[1] >ryan@DevPC-LX:~/golf/xktp$ # oops
ryan@DevPC-LX:~/golf/xktp$ python xktp.py
[1] >RANGE("2")
 = ("2", "3", "2", "3")
[2] >RANGE(2*1)
Traceback (most recent call last):
  File "xktp.py", line 31, in <module>
    for x in str(eval(l)).split('\n'):print ' =',x
  File "<string>", line 1, in <module>
  File "xktp.py", line 15, in RANGE
    def RANGE(a,b=0):return 2*(a,S(chr(ord(a)+1)))if b==0 else tuple([a]+[b-1,a+2]*((b-a)/4)+[b-1,b])
TypeError: ord() expected a character, but string of length 19 found
ryan@DevPC-LX:~/golf/xktp$ python xktp.py # oops again
[1] >RANGE(1,20)
 = (1, 19, 3, 19, 3, 19, 3, 19, 3, 19, 20)
[2] >RANGE(1,5)
 = (1, 4, 3, 4, 5)
[3] >RANGE(10,20)
 = (10, 19, 12, 19, 12, 19, 20)
[4] >RANGE(10,200)
 = (10, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 12, 199, 200)
[5] >+2
 = 52
[6] >+"99"
Traceback (most recent call last):
  File "xktp.py", line 31, in <module>
    for x in str(eval(l)).split('\n'):print ' =',x
  File "<string>", line 1, in <module>
TypeError: bad operand type for unary +: 'S'
ryan@DevPC-LX:~/golf/xktp$ python xktp.py # oops again and again!
[1] >FLOOR(200)
 = |
 = |
 = |
 = |___200___
[2] >2+2
 = DONE
[3] >3+#
Traceback (most recent call last):
  File "xktp.py", line 31, in <module>
    for x in str(eval(l)).split('\n'):print ' =',x
  File "<string>", line 1
    I(3)+#
         ^
SyntaxError: unexpected EOF while parsing
ryan@DevPC-LX:~/golf/xktp$ python xktp.py
[1] >3+3
 = DONE
[2] >ryan@DevPC-LX:~/golf/xktp$
```
[Answer]
# C, 412 bytes
This is basically hardcoded, but all the other answers so far were missing something...
```
i;char b[99];main(){for(;;){printf("[%d]>",abs(++i));gets(b);i-=b[2]==50?26:0;printf("=>");puts(*b==82?b[6]==34?"('\"',\"!\",\" \",\"!\",'\"')":"(1,4,3,4,5)":*b==70?"|\n=>|\n=>|\n=>|___10.5___":*b==43?"12":*b==91?b[8]==50?"FALSE":"TRUE":*b==34?b[1]==34?"'\"+\"'":"\"[2]\"":*b==40?b[5]==43?"NaP":"NaN":*b==99?b[7]=='s'?"rainbow":b[12]==98?"#0000FF":"NaN":b[1]==43?b[2]==34?"\"4\"":"DONE":"NaN.000000000000013");}}
```
Output:
```
[1]>2+"2"
=>"4"
[2]>"2"+[]
=>"[2]"
[3]>(2/0)
=>NaN
[4]>(2/0)+2
=>NaP
[5]>""+""
=>'"+"'
[6]>[1,2,3]+2
=>FALSE
[7]>[1,2,3]+4
=>TRUE
[8]>2/(2-(3/2+1/2))
=>NaN.000000000000013
[9]>RANGE(" ")
=>('"',"!"," ","!",'"')
[10]>+2
=>12
[11]>2+2
=>DONE
[14]>RANGE(1,5)
=>(1,4,3,4,5)
[13]>FLOOR(10.5)
=>|
=>|
=>|
=>|___10.5___
```
[Answer]
## Python 3, 298
Everything is hardcoded, but the input is turned into a number that is then converted to a string and looked up in a large string that contains all these numbers followed by their answers.
```
B="""53"#0000FF"~62DONE~43NaN.000000000000013~25(1,4,3,4,5)~26"rainbow"~49"4"~21"[2]"~29FALSE~15|*|*|*|___10.5___~17'"+"'~1212~60('"',"!"," ","!",'"')~24NaN~31TRUE~64NaN~76NaP"""
i=0
while 1:i+=1;s=input("[%s]>"%i);print("=>"+B[B.find(str(sum(map(ord,s))%81))+2:].split("~")[0].replace("*","\n=>"))
```
[Answer]
# Python 3, 542 484 bytes
Since there was no mention of absolute hardcoding here's my solution.
```
a={'2+"2"':'"4"','"2"+[]':'"[2]"',"(2/0)":"NaN","(2/0)+2":"NaP",'""+""':"'\"+\"'","[1,2,3]+2":"FALSE","[1,2,3]+4":"TRUE","2/(2-(3/2+1/2))":"NaN.000000000000013",'RANGE(" ")':'(\'"\',"!"," ","!",\'"\')',"+2":"12","2+2":"DONE","RANGE(1,5)":"(1,4,3,4,5)","FLOOR(10.5)":"|\n|\n|\n|___10.5___",'colors.rgb("blue")':'"#0000FF"','colors.rgb("yellowish blue")':"NaN","colors.sort()":'"rainbow"'}
i=1
while 1:b=a[input("[%i]>"%i).replace("\t","")].split("\n");print("=> "+"\n=> ".join(b));i+=1
```
]