Comma quibbling is a task originally set by Eric Lippert in his blog.



Task

Write a function to generate a string output which is the concatenation of input words from a list/sequence where:

 An input of no words produces the output string of just the two brace characters "{}".
 An input of just one word, e.g. ["ABC"], produces the output string of the word inside the two braces, e.g. "{ABC}".
 An input of two words, e.g. ["ABC", "DEF"], produces the output string of the two words inside the two braces with the words separated by the string " and ", e.g. "{ABC and DEF}".
 An input of three or more words, e.g. ["ABC", "DEF", "G", "H"], produces the output string of all but the last word separated by ", " with the last word separated by " and " and all within braces; e.g. "{ABC, DEF, G and H}".


Test your function with the following series of inputs showing your output here on this page:

 [] # (No input words).
 ["ABC"]
 ["ABC", "DEF"]
 ["ABC", "DEF", "G", "H"]


Note: Assume words are non-empty strings of uppercase characters for this task.




To quibble four words:
Add "ABC" to some string things.
Add "DEF" to the string things.
Add "G" to the string things.
Add "H" to the string things.
Quibble the string things.
 
To quibble one word:
Add "ABC" to some string things.
Quibble the string things.
 
To quibble some string things:
Quibble the string things giving a string.
Destroy the string things.
Write the string on the console.
 
To quibble some string things giving a string:
Append "{" to the string.
Put the string things' count into a count.
If the count is 0, append "}" to the string; exit.
Get a string thing from the string things.
If the count is 1, append the string thing's string then "}" to the string; exit.
Loop.
If a counter is past the count minus 2, append the string thing's string then " and " then the string thing's next's string then "}" to the string; exit.
Append the string thing's string then ", " to the string.
Put the string thing's next into the string thing.
Repeat.
 
To quibble two words:
Add "ABC" to some string things.
Add "DEF" to the string things.
Quibble the string things.
 
To quibble zero words:
Quibble some string things.
 
To run:
Start up.
Quibble zero words.
Quibble one word.
Quibble two words.
Quibble four words.
Wait for the escape key.
Shut down.