[3745] | 1 | ###########################################################################
|
---|
| 2 | #
|
---|
| 3 | # help.mg.src -- Source for the help command
|
---|
| 4 | # Copyright (C) 1994 Neil Sharman
|
---|
| 5 | #
|
---|
| 6 | # This program is free software; you can redistribute it and/or modify
|
---|
| 7 | # it under the terms of the GNU General Public License as published by
|
---|
| 8 | # the Free Software Foundation; either version 2 of the License, or
|
---|
| 9 | # (at your option) any later version.
|
---|
| 10 | #
|
---|
| 11 | # This program is distributed in the hope that it will be useful,
|
---|
| 12 | # but WITHOUT ANY WARRANTY; without even the implied warranty of
|
---|
| 13 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
---|
| 14 | # GNU General Public License for more details.
|
---|
| 15 | #
|
---|
| 16 | # You should have received a copy of the GNU General Public License
|
---|
| 17 | # along with this program; if not, write to the Free Software
|
---|
| 18 | # Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
|
---|
| 19 | #
|
---|
| 20 | # @(#)help.mg.src 1.8 21 Mar 1994
|
---|
| 21 | #
|
---|
| 22 | ###########################################################################
|
---|
| 23 | #
|
---|
| 24 | # The help file for mgquery.
|
---|
| 25 | # Lines starting with '#' are treated as comments and are discarded when
|
---|
| 26 | # the 'help.mg.h' file is produced
|
---|
| 27 | #
|
---|
| 28 | ###########################################################################
|
---|
| 29 |
|
---|
| 30 | HELP for mgquery
|
---|
| 31 | ================================
|
---|
| 32 |
|
---|
| 33 | The text is a summary of the information in the "mgquery" manual pages.
|
---|
| 34 |
|
---|
| 35 | The input to 'mgquery' consists of a series of input lines. The backslash
|
---|
| 36 | character ("\") is used at the end of lines to indicate that input
|
---|
| 37 | continues on the next line.
|
---|
| 38 |
|
---|
| 39 | Input lines on which the first character is a dot (".") are commands to
|
---|
| 40 | the mgquery program. Input lines that do not start with a dot are queries.
|
---|
| 41 |
|
---|
| 42 | A query consists of two parts. One part is a boolean or ranked query that
|
---|
| 43 | identifies documents. The second part is a post-processing pattern matching
|
---|
| 44 | operation. Any text between the first speech mark (") and the last speech
|
---|
| 45 | mark is considered to the a post-processing pattern.
|
---|
| 46 |
|
---|
| 47 |
|
---|
| 48 | The following command are available :-
|
---|
| 49 |
|
---|
| 50 | .help - displays this text.
|
---|
| 51 | .quit - quits the program.
|
---|
| 52 | .set name value - sets parameter "name" to "value" . If the parameter
|
---|
| 53 | is a boolean parameter and value is omitted the
|
---|
| 54 | parameter will be inverted (i.e. if it is true it
|
---|
| 55 | will change to false, if it is false it will change
|
---|
| 56 | to true).
|
---|
| 57 | .unset name - deletes parameter "name"
|
---|
| 58 | .reset - sets all the parameters to their initial state.
|
---|
| 59 | .display - displays the values of all the current parameters.
|
---|
| 60 | .push - pushes the current parameters on to a stack.
|
---|
| 61 | .pop - destroys the current parameters and pops a new set
|
---|
| 62 | of parameters off the stack.
|
---|
| 63 | .output arg - This is used to specify where to send the documents.
|
---|
| 64 | Arg may one be of the following:
|
---|
| 65 | > filename : Send output to the specified file.
|
---|
| 66 | >> filename : Append output to the specified file.
|
---|
| 67 | | command : The output is piped into command,
|
---|
| 68 | which is executed by sh.
|
---|
| 69 | .input arg - This is used to specify where input comes from.
|
---|
| 70 | Arg may one be of the following:
|
---|
| 71 | < filename : Get the input from the specified
|
---|
| 72 | file.
|
---|
| 73 | | command : The input comes from the standard
|
---|
| 74 | output of command, which is executed
|
---|
| 75 | by sh.
|
---|
| 76 |
|
---|
| 77 | On startup the mgquery program reads from the file .mgrc a sequence
|
---|
| 78 | of commands (NOTE: The .mgrc file may not contain any queries). mgquery
|
---|
| 79 | first looks for .mgrc in the current directory and then in the users home
|
---|
| 80 | directory. Lines starting with a '#' in the .mgrc file are considered to
|
---|
| 81 | be comments and are ignored.
|
---|
| 82 |
|
---|
| 83 | The following parameters (used in the .set and .unset commands) are
|
---|
| 84 | predefined and have special significance :-
|
---|
| 85 |
|
---|
| 86 | accumulator_method = `array'
|
---|
| 87 | This parameter is used during ranking, and specifies how the
|
---|
| 88 | weight for each document should be accumulated. The following
|
---|
| 89 | methods are available `array', `splay_tree', `hash_table', and
|
---|
| 90 | `list'.
|
---|
| 91 |
|
---|
| 92 | briefstats = `off'
|
---|
| 93 | This is a boolean parameter that determines whether the the
|
---|
| 94 | totals for disk, memory and time usage statistics will be
|
---|
| 95 | displayed. at the end of each query.
|
---|
| 96 | NOTE: this takes precedence over the parameters "diskstats",
|
---|
| 97 | "memstats" and "timestats". This parameter may take the values
|
---|
| 98 | `yes', `no', `true', `false', `on' or `off'.
|
---|
| 99 |
|
---|
| 100 | buffer = `1048576'
|
---|
| 101 | When the documents are being read in they are read into a
|
---|
| 102 | buffer of this size and then displayed from this buffer. If
|
---|
| 103 | the documents are larger than this buffer the buffer is
|
---|
| 104 | expanded automatically. Having a large buffer gives a very
|
---|
| 105 | slight performance improvement because it allows the order of
|
---|
| 106 | disk operations to be optimised. The buffer size is measured
|
---|
| 107 | in bytes.
|
---|
| 108 |
|
---|
| 109 | diskstats = `off'
|
---|
| 110 | This is a boolean parameter that determines whether the disk
|
---|
| 111 | usage statistics for the preceding query will be displayed
|
---|
| 112 | after each query. This parameter may take the values `yes',
|
---|
| 113 | `no', `true', `false', `on' or `off'.
|
---|
| 114 |
|
---|
| 115 | doc_sepstr = `---------------------------------- %n\n'
|
---|
| 116 | This specifies the string that will be used to separate
|
---|
| 117 | documents when they are displayed for `boolean' or `docnums'
|
---|
| 118 | queries. The standard C escape character sequences (see the
|
---|
| 119 | man page) may be used to place special characters in the
|
---|
| 120 | string. For example, a newline would the `\n'. To include a `%'
|
---|
| 121 | use the sequence `%%'. To include the MG document number use
|
---|
| 122 | the sequence `%n'.
|
---|
| 123 |
|
---|
| 124 | expert = `false'
|
---|
| 125 | If this is true then a lot of the waffle that the program
|
---|
| 126 | spits out is suppressed. This parameter may take the values
|
---|
| 127 | `yes', `no', `true', `false', `on' or `off'.
|
---|
| 128 |
|
---|
| 129 | hash_tbl_size = `1000'
|
---|
| 130 | One of the options during ranking queries is to use a hash
|
---|
| 131 | table to accumulate the weights for each document. The hash
|
---|
| 132 | table is a simple chained type. This parameter specifies the
|
---|
| 133 | size of the hash table and may take any value between 8 and
|
---|
| 134 | 268435456.
|
---|
| 135 |
|
---|
| 136 | heads_length = `50'
|
---|
| 137 | When the mode is `heads' this specifies the number of
|
---|
| 138 | characters that will be output for each document.
|
---|
| 139 |
|
---|
| 140 | maxdocs = `all'
|
---|
| 141 | The maximum number of documents to display in response to a
|
---|
| 142 | query. This parameter may take on a numeric value between 1
|
---|
| 143 | and 429467295 or the word `all'.
|
---|
| 144 |
|
---|
| 145 | maxparas = `1000'
|
---|
| 146 | The maximum number of paragraphs to identify during a ranked
|
---|
| 147 | query with paragraph indexing. After the paragraphs have been
|
---|
| 148 | identified the paragraphs are converted into documents, and
|
---|
| 149 | because some of the paragraphs may refer to the same documents
|
---|
| 150 | the final number of answers may be less that maxparas. The
|
---|
| 151 | maxdocs parameter will then be applied. This parameter may
|
---|
| 152 | take on a numeric value between 1 and 429467295.
|
---|
| 153 |
|
---|
| 154 | max_accumulators = `50000'
|
---|
| 155 | This parameter limits the number of different paragraph/
|
---|
| 156 | document numbers to be accumulated during ranked queries when
|
---|
| 157 | the parameter `accumulator_method` is set to `splay_tree',
|
---|
| 158 | `hash_table', or `list'. This parameter may take any value
|
---|
| 159 | between 8 and 268435456.
|
---|
| 160 |
|
---|
| 161 | max_terms = `all'
|
---|
| 162 | This parameter limits the number of terms that will actually
|
---|
| 163 | be used during a ranked query. If more terms than the number
|
---|
| 164 | specified by max_terms are entered, then the extra terms will
|
---|
| 165 | be discarded. If `sorted_terms' is on then the limiting will
|
---|
| 166 | be done after the terms have been sorted. This parameter may
|
---|
| 167 | take any value between 1 and 429467295 or the word `all'.
|
---|
| 168 |
|
---|
| 169 | memstats = `off'
|
---|
| 170 | This is a boolean parameter that determines whether the memory
|
---|
| 171 | usage statistics for the preceding query will be displayed
|
---|
| 172 | after each query. This parameter may take the values `yes',
|
---|
| 173 | `no', `true', `false', `on' or `off'.
|
---|
| 174 |
|
---|
| 175 | mgdir = `.'
|
---|
| 176 | This specifies the directory where the MG files may be found.
|
---|
| 177 | If the environment variable `MGDATA' is set then `mgdir' is
|
---|
| 178 | initialised to the value in `MGDATA'.
|
---|
| 179 |
|
---|
| 180 | mgname = `'
|
---|
| 181 | This specifies the name of the MG database to process.
|
---|
| 182 |
|
---|
| 183 | mode = `text'
|
---|
| 184 | This specifies how documents should be displayed when they
|
---|
| 185 | are retrieved it may take four different values `text',
|
---|
| 186 | `docnums', `silent', `heads' or `count'. `text' displays
|
---|
| 187 | the contents of the document. `docnums' displays only the
|
---|
| 188 | document numbers. `Silent' retrieves all the documents but
|
---|
| 189 | displays nothing except how many documents were retrieved.
|
---|
| 190 | This mode is intended to be used in timing experiments.
|
---|
| 191 | `Heads` is used to print out the head of each document.
|
---|
| 192 | `Count' does the minimum amount of work required to determine
|
---|
| 193 | how many documents would be retrieved, but does not retrieve
|
---|
| 194 | them.
|
---|
| 195 |
|
---|
| 196 | pager = `more'
|
---|
| 197 | This is the name of the program that will be used to display
|
---|
| 198 | the help and the retrieved documents. If the environment
|
---|
| 199 | variable "PAGER" is defined then `pager' takes on that value.
|
---|
| 200 |
|
---|
| 201 | para_sepstr = `\n######## PARAGRAPH %n ########\n'
|
---|
| 202 | This specifies the string that will be used to separate
|
---|
| 203 | paragraphs. The standard C escape character sequences (see the
|
---|
| 204 | man page) may be used to place special characters in the
|
---|
| 205 | string. For example, a newline would the `\n'. To include a `%'
|
---|
| 206 | use the sequence `%%'. To include the paragraph number within
|
---|
| 207 | the document use the sequence `%n'.
|
---|
| 208 |
|
---|
| 209 | para_start = `***** Weight = %w *****\n'
|
---|
| 210 | This specifies the string that will be used at the head of
|
---|
| 211 | paragraphs for a paraghaph level index following a ranked query.
|
---|
| 212 | The standard C escape character sequences (see the man page)
|
---|
| 213 | may be used to place special characters in the string. For
|
---|
| 214 | example, a newline would the `\n'. To include a `%' use the
|
---|
| 215 | sequence `%%'. To include the paragraph weight use the
|
---|
| 216 | sequence `%w'.
|
---|
| 217 |
|
---|
| 218 | qfreq = `true'
|
---|
| 219 | This determine whether the ranked queries will take into
|
---|
| 220 | account the number of times each query term is specified.
|
---|
| 221 | When this is `true' the number of times a term appears in
|
---|
| 222 | the query is used in the ranking. When this is `false' all
|
---|
| 223 | query term are assumed to occur only once. This parameter
|
---|
| 224 | may take the values `yes', `no', `true', `false', `on' or
|
---|
| 225 | `off'.
|
---|
| 226 |
|
---|
| 227 | query = `boolean'
|
---|
| 228 | This specifies the type of queries that are to be specified.
|
---|
| 229 | It can take four different values `boolean', `ranked',
|
---|
| 230 | `docnums' or `approx-ranked'.
|
---|
| 231 |
|
---|
| 232 | `boolean' is for boolean queries.
|
---|
| 233 | The yacc grammar for boolean queries is as follows :-
|
---|
| 234 |
|
---|
| 235 | query : or;
|
---|
| 236 |
|
---|
| 237 | or : or '|' and
|
---|
| 238 | | and ;
|
---|
| 239 |
|
---|
| 240 | and : and '&' not
|
---|
| 241 | | and not
|
---|
| 242 | | not ;
|
---|
| 243 |
|
---|
| 244 | not : term
|
---|
| 245 | | '!' not ;
|
---|
| 246 |
|
---|
| 247 | term : TERM
|
---|
| 248 | | '(' or ')' ;
|
---|
| 249 |
|
---|
| 250 |
|
---|
| 251 |
|
---|
| 252 |
|
---|
| 253 | `ranked' and `approx-ranked' are for queries ranked by the
|
---|
| 254 | cosine measure. `approx-ranked' uses only the low
|
---|
| 255 | precision document lengths, and therefore only
|
---|
| 256 | produces an approximation to full cosine ranking.
|
---|
| 257 |
|
---|
| 258 | query : TERM
|
---|
| 259 | | query TERM ;
|
---|
| 260 |
|
---|
| 261 | `docnums' allows the entry of document numbers. Multiple
|
---|
| 262 | numbers separated by spaces may be specified
|
---|
| 263 | or ranges separated by hyphens.
|
---|
| 264 |
|
---|
| 265 |
|
---|
| 266 | query : range
|
---|
| 267 | | query range ;
|
---|
| 268 |
|
---|
| 269 |
|
---|
| 270 | range : num
|
---|
| 271 | | num '-' num ;
|
---|
| 272 |
|
---|
| 273 |
|
---|
| 274 | ranked_doc_sepstr = `---------------------------------- %n %w\n'
|
---|
| 275 | This specifies the string that will be used to separate
|
---|
| 276 | documents when they are displayed for `ranked' or
|
---|
| 277 | `approx-ranked' queries. The standard C escape character
|
---|
| 278 | sequences (see the man page) may be used to place special
|
---|
| 279 | characters in the string. For example, a newline would the
|
---|
| 280 | `\n'. To include a `%' use the sequence `%%'. To include the
|
---|
| 281 | MG document number use the sequence `%n'. To include the
|
---|
| 282 | document weight use the sequence `%w'.
|
---|
| 283 |
|
---|
| 284 | sizestats = `false'
|
---|
| 285 | If this is true then various numbers are output at the end
|
---|
| 286 | of each query indicating what went on during the query.
|
---|
| 287 | This parameter may take the values `yes', `no', `true',
|
---|
| 288 | `false', `on' or `off'.
|
---|
| 289 |
|
---|
| 290 | skip_dump = `skips.%d'
|
---|
| 291 | If this parameter is set then during ranked queries on skipped
|
---|
| 292 | inverted files when `accumulator_method' is set to `splay_tree',
|
---|
| 293 | `hash_table', or `list` a file will be produced in the current
|
---|
| 294 | directory. The name of the file is the value of this parameter,
|
---|
| 295 | a `%d' in the file name will be replaced with the process id of
|
---|
| 296 | mgquery. This file will contain information about the usage of
|
---|
| 297 | skips during the query processing. This option is expensive;
|
---|
| 298 | use `.unset skip_dump' to obtain optimal performance.
|
---|
| 299 |
|
---|
| 300 | sorted_terms = `on'
|
---|
| 301 | This specifies whether of not the terms should be sorted into
|
---|
| 302 | decreasing occurrence in documents so that the least often
|
---|
| 303 | occurring terms are processed first when ranked queries are
|
---|
| 304 | being done. When this is true the terms are sorted. When this
|
---|
| 305 | is false the terms are not sorted and are instead processed in
|
---|
| 306 | order of occurrence. This parameter may take the values `yes',
|
---|
| 307 | `no', `true', `false', `on' or `off'.
|
---|
| 308 |
|
---|
| 309 |
|
---|
| 310 | stop_at_max_accum = `on'
|
---|
| 311 | This specifies what should happen when the maximum number of
|
---|
| 312 | accumulators set by `max_accumulators' is reached. When this
|
---|
| 313 | is true the the processing of terms is stopped at the completion
|
---|
| 314 | of the current term. When this is false processing continues but
|
---|
| 315 | no new accumulators are created. This parameter may take the
|
---|
| 316 | values `yes', `no', `true', `false', `on' or `off'.
|
---|
| 317 |
|
---|
| 318 | terminator = `'
|
---|
| 319 | This specifies the string that will be output after the last
|
---|
| 320 | document from the previous query has been output. The standard
|
---|
| 321 | C escape character sequences (see the man page) may be used to
|
---|
| 322 | place special characters in the string. For example, a newline
|
---|
| 323 | would the `\n'. To include a `%' use the sequence `%%'.
|
---|
| 324 |
|
---|
| 325 |
|
---|
| 326 | timestats = `false'
|
---|
| 327 | If this is true then the time to process a query is displayed
|
---|
| 328 | in both real time and CPU time. This parameter may take the
|
---|
| 329 | values `yes', `no', `true', `false', `on' or `off'.
|
---|
| 330 |
|
---|
| 331 | verbatim = `off'
|
---|
| 332 | This is a boolean parameter that determines whether the program
|
---|
| 333 | should attempt to do a regular expression match on the retrieved
|
---|
| 334 | text. If verbatim is `on' and a post-processing strng is specified
|
---|
| 335 | with the query then the post-processing string will be searched for
|
---|
| 336 | in the documents just before they are displayed. If the string is
|
---|
| 337 | found the document will be displayed, if not the document will not
|
---|
| 338 | be displayed. If verbatim is `off' the post-processing string will
|
---|
| 339 | be considered a regular expression like in `vi' or `egrep'.
|
---|
| 340 | E.G. If verbatim is `on', "and.*the" will look for the 8 character
|
---|
| 341 | sequence "and.*the". If verbatim is `off', "and.*the" will
|
---|
| 342 | look for the sequence "and" followed somewhere later in the
|
---|
| 343 | document by the sequence "the".
|
---|
| 344 | This parameter may take the values `yes', `no', `true', `false',
|
---|
| 345 | `on' or `off'.
|
---|
| 346 |
|
---|
| 347 |
|
---|