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# @(#)input 5.5 (Berkeley) 7/2/94 MAPS, EXECUTABLE BUFFERS AND INPUT IN EX/VI: The basic rule is that input in ex/vi is a stack. Every time a key which gets expanded is encountered, it is expanded and the expansion is treated as if it were input from the user. So, maps and executable buffers are simply pushed onto the stack from which keys are returned. The exception is that if the "remap" option is turned off, only a single map expansion is done. I intend to be fully backward compatible with this. Historically, if the mode of the editor changed (ex to vi or vice versa), any queued input was silently discarded. I don't see any reason to either support or not support this semantic. I intend to retain the queued input, mostly because it's simpler than throwing it away. Historically, neither the initial command on the command line (the + flag) or the +cmd associated with the ex and edit commands was subject to mapping. Also, while the +cmd appears to be subject to "@buffer" expansion, once expanded it doesn't appear to work correctly. I don't see any reason to either support or not support these semantics, so, for consistency, I intend to pass both the initial command and the command associated with ex and edit commands through the standard mapping and @ buffer expansion. One other difference between the historic ex/vi and nex/nvi is that nex displays the executed buffers as it executes them. This means that if the file is: set term=xterm set term=yterm set term=yterm the user will see the following during a typical edit session: nex testfile testfile: unmodified: line 3 :1,$yank a :@a :set term=zterm :set term=yterm :set term=xterm :q! This seems like a feature and unlikely to break anything, so I don't intend to match historic practice in this area. The rest of this document is a set of conclusions as to how I believe the historic maps and @ buffers work. The summary is as follows: 1: For buffers that are cut in "line mode", or buffers that are not cut in line mode but which contain portions of more than a single line, a trailing <newline> character appears in the input for each line in the buffer when it is executed. For buffers not cut in line mode and which contain portions of only a single line, no additional characters appear in the input. 2: Executable buffers that execute other buffers don't load their contents until they execute them. 3: Maps and executable buffers are copied when they are executed -- they can be modified by the command but that does not change their actions. 4: Historically, executable buffers are discarded if the editor switches between ex and vi modes. 5: Executable buffers inside of map commands are expanded normally. Maps inside of executable buffers are expanded normally. 6: If an error is encountered while executing a mapped command or buffer, the rest of the mapped command/buffer is discarded. No user input characters are discarded. 7: Characters in executable buffers are remapped. 8: Characters in executable buffers are not quoted. Individual test cases follow. Note, in the test cases, control characters are not literal and will have to be replaced to make the test cases work. =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= 1: For buffers that are cut in "line mode", or buffers that are not cut in line mode but which contain portions of more than a single line, a trailing <newline> character appears in the input for each line in the buffer when it is executed. For buffers not cut in line mode and which contain portions of only a single line, no additional characters appear in the input. === test file === 3Gw w line 1 foo bar baz line 2 foo bar baz line 3 foo bar baz === end test file === If the first line is loaded into 'a' and executed: 1G"ayy@a The cursor ends up on the '2', a result of pushing "3Gw^J" onto the stack. If the first two lines are loaded into 'a' and executed: 1G2"ayy@a The cursor ends up on the 'f' in "foo" in the fifth line of the file, a result of pushing "3Gw^Jw^J" onto the stack. If the first line is loaded into 'a', but not using line mode, and executed: 1G"ay$@a The cursor ends up on the '1', a result of pushing "3Gw" onto the stack If the first two lines are loaded into 'a', but not using line mode, and executed: 1G2"ay$@a The cursor ends up on the 'f' in "foo" in the fifth line of the file, a result of pushing "3Gw^Jw^J" onto the stack. =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= 2: Executable buffers that execute other buffers don't load their contents until they execute them. === test file === cwLOAD B^[ line 1 foo bar baz line 2 foo bar baz line 3 foo bar baz @a@b "byy === end test file === The command is loaded into 'e', and then executed. 'e' executes 'a', which loads 'b', then 'e' executes 'b'. 5G"eyy6G"ayy1G@e The output should be: === output file === cwLOAD B^[ LOAD B 1 foo bar baz line 2 foo bar baz line 3 foo bar baz @a@b "byy === end output file === =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= 3: Maps and executable buffers are copied when they are executed -- they can be modified by the command but that does not change their actions. Executable buffers: === test file === line 1 foo bar baz line 2 foo bar baz line 3 foo bar baz @a@b "eyy cwEXECUTE B^[ === end test file === 4G"eyy5G"ayy6G"byy1G@eG"ep The command is loaded into 'e', and then executed. 'e' executes 'a', which loads 'e', then 'e' executes 'b' anyway. The output should be: === output file === line 1 foo bar baz EXECUTE B 2 foo bar baz line 3 foo bar baz @a@b "eyy cwEXECUTE B^[ line 1 foo bar baz === end output file === Maps: === test file === Cine 1 foo bar baz line 2 foo bar baz line 3 foo bar baz === end test file === Entering the command ':map = :map = rB^V^MrA^M1G==' shows that the first time the '=' is entered the '=' map is set and the character is changed to 'A', the second time the character is changed to 'B'. =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= 4: Historically, executable buffers are discarded if the editor switches between ex and vi modes. === test file === line 1 foo bar baz line 2 foo bar baz line 3 foo bar baz cwCHANGE^[Q:set set|visual|1Gwww === end test file === vi testfile 4G"ayy@a ex testfile $p yank a @a In vi, the command is loaded into 'a' and then executed. The command subsequent to the 'Q' is (historically, silently) discarded. In ex, the command is loaded into 'a' and then executed. The command subsequent to the 'visual' is (historically, silently) discarded. The first set command is output by ex, although refreshing the screen usually causes it not to be seen. =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= 5: Executable buffers inside of map commands are expanded normally. Maps inside of executable buffers are expanded normally. Buffers inside of map commands: === test file === line 1 foo bar baz line 2 foo bar baz line 3 foo bar baz cwREPLACE BY A^[ === end test file === 4G"ay$:map x @a 1Gx The output should be: === output file === REPLACE BY A 1 foo bar baz line 2 foo bar baz line 3 foo bar baz cwREPLACE BY A^[ === end output file === Maps commands inside of executable buffers: === test file === line 1 foo bar baz line 2 foo bar baz line 3 foo bar baz X === end test file === :map X cwREPLACE BY XMAP^[ 4G"ay$1G@a The output should be: === output file === REPLACE BY XMAP 1 foo bar baz line 2 foo bar baz line 3 foo bar baz X === end output file === Here's a test that does both, repeatedly. === test file === line 1 foo bar baz line 2 foo bar baz line 3 foo bar baz X Y cwREPLACED BY C^[ blank line === end test file === :map x @a 4G"ay$ :map X @b 5G"by$ :map Y @c 6G"cy$ 1Gx The output should be: === output file === REPLACED BY C 1 foo bar baz line 2 foo bar baz line 3 foo bar baz X Y cwREPLACED BY C^[ blank line === end output file === =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= 6: If an error is encountered while executing a mapped command or a buffer, the rest of the mapped command/buffer is discarded. No user input characters are discarded. === test file === line 1 foo bar baz line 2 foo bar baz line 3 foo bar baz :map = 10GcwREPLACMENT^V^[^[ === end test file === The above mapping fails, however, if the 10G is changed to 1, 2, or 3G, it will succeed. =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= 7: Characters in executable buffers are remapped. === test file === abcdefghijklmnnop ggg === end test file === :map g x 2G"ay$1G@a The output should be: === output file === defghijklmnnop ggg === end output file === =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= 8: Characters in executable buffers are not quoted. === test file === iFOO^[ === end test file === 1G"ay$2G@a The output should be: === output file === iFOO^[ FOO === end output file === =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=