pmarin. ReadChar is an implementation of the classic getc and putbak functions.
For more info see the page 255 of Software Tools by Kernighan and Plauger.
The code is part of Muddy Scheme
package require TclOO package require struct::stack oo::class create ReadChar { constructor {{chan stdin}} { my variable ch my variable buf set ch $chan set buf [struct::stack] } method getc {} { my variable ch my variable buf if {[$buf size]} { return [$buf pop] } else { if {![eof $ch]} { return [read $ch 1] } else { return "eof" } } } method eof {} { my variable ch my variable buf if { ![$buf size] && [eof $ch] } { return 1 } else { return 0 } } method peek {} { my variable ch my variable buf if {[$buf size]} { return [$buf peek] } else { if {![eof $ch]} { set c [read $ch 1] $buf push $c return $c } else { return "eof" } } } method putbak str { my variable buf if { [string length $str] > 0 } { if { [string length $str] == 1 } { $buf push $str } else { foreach i [split [string reverse $str] {}] { $buf push $i } } } } destructor { my variable ch my variable buf $buf destroy close $ch } }
It is rare that It is not already implemented in the core libraries... Am I missing something?