Generate code for loops

TODO

@@ -3,19 +3,17 @@
 - Catch exceptions thrown by the argument parser and print them normally.
 - Structs or records.
 - Unions.
-- While loop.
 - Type checking.
-- Calculate additional stack space needed for subexpressions in the allocator
-  visitor and not in the backend.
 - Support immediates greater than 12 bits.
 - It seems instructions are correctly encoded only if the compiler is running
   on a little endian architecture.
 - Assignment to a pointer.
 - Static array.
 - Syscalls.
+- Error message with an empty file wrongly says that a ")" is expected.
+- Support any expressions for constants.
 
 # Shell
-- Persist the history.
 - Replace hard coded ANSI codes with constants or functions.
 
 ## Completion
@@ -25,4 +23,3 @@
 - Don't hardcode fzf binary path.
 - Send the word under the cursor to fzf as initial input.
 - Home directory expansion.
-- Show files in the PATH if starting at the beginning of the prompt