Return to rsg.1 CVS log

Up to [CSRG BSD Unix] / 43BSD / contrib / icon / man / cat1

Annotation of 43BSD/contrib/icon/man/cat1/rsg.1, revision 1.1

1.1     ! root        1: 
        !             2: 
        !             3: 
        !             4: RSG(1)                Icon Program Library                 RSG(1)
        !             5: 
        !             6: 
        !             7: 
        !             8: NNNNAAAAMMMMEEEE
        !             9:      rsg - generate random sentences
        !            10: 
        !            11: SSSSYYYYNNNNOOOOPPPPSSSSIIIISSSS
        !            12:      rrrrssssgggg [----llll _n] [----llll _n] [----tttt]
        !            13: 
        !            14: DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN
        !            15:      _R_s_g generates randomly selected sentences from a grammar
        !            16:      specified by the user.
        !            17: 
        !            18:      The following options may appear in any order:
        !            19: 
        !            20:      ----ssss _n Set the seed for random generation to _n.  The default
        !            21:           seed is 0.
        !            22: 
        !            23:      ----llll _n Terminate generation if the number of symbols remaining
        !            24:           to be processed exceeds _n. There is no default limit.
        !            25: 
        !            26:      ----tttt   Trace the generation of sentences. Trace output goes to
        !            27:           standard error output.
        !            28: 
        !            29:      _R_s_g works interactively, allowing the user to build, test,
        !            30:      modify, and save grammars. Input to _r_s_g consists of various
        !            31:      kinds of specifications, which can be intermixed:
        !            32: 
        !            33:      _P_r_o_d_u_c_t_i_o_n_s define nonterminal symbols in a syntax similar
        !            34:      to the rewriting rules of BNF with various alternatives con-
        !            35:      sisting of the concatenation of nonterminal and terminal
        !            36:      symbols.
        !            37: 
        !            38:      _G_e_n_e_r_a_t_i_o_n _s_p_e_c_i_f_i_c_a_t_i_o_n_s cause the generation of a speci-
        !            39:      fied number of sentences from the language defined by a
        !            40:      given nonterminal symbol.
        !            41: 
        !            42:      _G_r_a_m_m_a_r _o_u_t_p_u_t _s_p_e_c_i_f_i_c_a_t_i_o_n_s cause the definition of a
        !            43:      specified nonterminal or the entire current grammar to be
        !            44:      written to a given file.
        !            45: 
        !            46:      _S_o_u_r_c_e _s_p_e_c_i_f_i_c_a_t_i_o_n_s cause subsequent input to be read from
        !            47:      a specified file.
        !            48: 
        !            49:      In addition, any line beginning with #### is considered to be a
        !            50:      comment, while any line beginning with ==== causes the rest of
        !            51:      that line to be used as a prompt to the user whenever _r_s_g is
        !            52:      ready for input (there normally is no prompt). A line con-
        !            53:      sisting of a single ==== stops prompting.
        !            54: 
        !            55:    PPPPrrrroooodddduuuuccccttttiiiioooonnnnssss
        !            56:      Examples of productions are:
        !            57: 
        !            58:           <expr>::=<term>|<term>+<expr>
        !            59:           <term>::=<element>|<element>*<term>
        !            60: 
        !            61: 
        !            62: 
        !            63: Version 5.9    The University of Arizona - 5/16/83              1
        !            64: 
        !            65: 
        !            66: 
        !            67: 
        !            68: 
        !            69: 
        !            70: RSG(1)                Icon Program Library                 RSG(1)
        !            71: 
        !            72: 
        !            73: 
        !            74:           <element>::=x|y|z|(<expr>)
        !            75: 
        !            76:      Productions may occur in any order. The definition for a
        !            77:      nonterminal symbol can be changed by specifying a new pro-
        !            78:      duction for it.
        !            79: 
        !            80:      There are a number of special devices to facilitate the
        !            81:      definition of grammars, including eight predefined, built-in
        !            82:      nonterminal symbols:
        !            83: 
        !            84:           symbol    definition
        !            85:           <<<<llllbbbb>>>>      <<<<
        !            86:           <<<<rrrrbbbb>>>>      >>>>
        !            87:           <<<<vvvvbbbb>>>>      ||||
        !            88:           <<<<nnnnllll>>>>      newline
        !            89:           <<<<>>>>        empty string
        !            90:           <<<<&&&&llllccccaaaasssseeee>>>>  any single lowercase letter
        !            91:           <<<<&&&&uuuuccccaaaasssseeee>>>>  any single uppercase letter
        !            92:           <<<<&&&&ddddiiiiggggiiiitttt>>>>  any single digit
        !            93: 
        !            94:      In addition, if the string between a <<<< and >>>> begins and ends
        !            95:      with a single quotation mark, that construction stands for
        !            96:      any single character between the quotation marks. For exam-
        !            97:      ple,
        !            98: 
        !            99:           <'xyz'>
        !           100: 
        !           101:      is equivalent to
        !           102: 
        !           103:           x|y|z
        !           104: 
        !           105:      Finally, if the name of a nonterminal symbol between the <<<<
        !           106:      and >>>> begins with ????, the user is queried during generation
        !           107:      to supply a string for that nonterminal symbol. For example,
        !           108:      in
        !           109: 
        !           110:           <expr>::=<term>|<term>+<expr>|<?expr>
        !           111: 
        !           112:      if the third alternative is encountered during generation,
        !           113:      the user is asked to provide a string for <<<<eeeexxxxpppprrrr>>>>.
        !           114: 
        !           115:    GGGGeeeennnneeeerrrraaaattttiiiioooonnnn SSSSppppeeeecccciiiiffffiiiiccccaaaattttiiiioooonnnnssss
        !           116:      A generation specification consists of a nonterminal symbol
        !           117:      followed by a nonnegative integer. An example is
        !           118: 
        !           119:           <expr>10
        !           120: 
        !           121:      which specifies the generation of 10 <<<<eeeexxxxpppprrrr>>>>s. If the integer
        !           122:      is omitted, it is assumed to be 1. Generated sentences are
        !           123:      written to standard output.
        !           124: 
        !           125: 
        !           126: 
        !           127: 
        !           128: 
        !           129: Version 5.9    The University of Arizona - 5/16/83              2
        !           130: 
        !           131: 
        !           132: 
        !           133: 
        !           134: 
        !           135: 
        !           136: RSG(1)                Icon Program Library                 RSG(1)
        !           137: 
        !           138: 
        !           139: 
        !           140:    GGGGrrrraaaammmmmmmmaaaarrrr OOOOuuuuttttppppuuuutttt SSSSppppeeeecccciiiiffffiiiiccccaaaattttiiiioooonnnnssss
        !           141:      A grammar output specification consists of a nonterminal
        !           142:      symbol, followed by ---->>>>, followed by a file name. Such a
        !           143:      specification causes the current definition of the nontermi-
        !           144:      nal symbol to be written to the given file. If the file is
        !           145:      omitted, standard output is assumed. If the nonterminal sym-
        !           146:      bol is omitted, the entire grammar is written out. Thus,
        !           147: 
        !           148:           ->
        !           149: 
        !           150:      causes the entire grammar to be written to standard output.
        !           151: 
        !           152:    SSSSoooouuuurrrrcccceeee SSSSppppeeeecccciiiiffffiiiiccccaaaattttiiiioooonnnnssss
        !           153:      A source specification consists of @@@@ followed by a file
        !           154:      name.  Subsequent input is read from that file. When an end
        !           155:      of file is encountered, input reverts to the previous file.
        !           156:      Input files can be nested.
        !           157: 
        !           158: DDDDIIIIAAAAGGGGNNNNOOOOSSSSTTTTIIIICCCCSSSS
        !           159:      Syntactically erroneous input lines are noted, but ignored.
        !           160: 
        !           161:      Specifications for a file that cannot be opened are noted
        !           162:      and treated as erroneous.
        !           163: 
        !           164:      If an undefined nonterminal symbol is encountered during
        !           165:      generation, an error message that identifies the undefined
        !           166:      symbol is produced, followed by the partial sentence gen-
        !           167:      erated to that point. Exceeding the limit of symbols remain-
        !           168:      ing to be generated as specified by the ----llll option is handled
        !           169:      in similarly.
        !           170: 
        !           171: CCCCAAAAVVVVEEEEAAAATTTTSSSS
        !           172:      Generation may fail to terminate because of a loop in the
        !           173:      rewriting rules or, more seriously, because of the progres-
        !           174:      sive accumulation of nonterminal symbols. The latter problem
        !           175:      can be identified by using the ----tttt option and controlled by
        !           176:      using the ----llll option. The problem often can be circumvented
        !           177:      by duplicating alternatives that lead to fewer rather than
        !           178:      more nonterminal symbols. For example, changing
        !           179: 
        !           180:           <expr>::=<term>|<term>+<expr>
        !           181: 
        !           182:      to
        !           183: 
        !           184:           <expr>::=<term>|<term>|<term>+<expr>
        !           185: 
        !           186:      increases the probability of selecting <<<<tttteeeerrrrmmmm>>>> from 1/2 to
        !           187:      2/3.  See the second reference listed below for a discussion
        !           188:      of the general problem.
        !           189: 
        !           190: SSSSEEEEEEEE AAAALLLLSSSSOOOO
        !           191:      Griswold, Ralph E. and Madge T. Griswold. _T_h_e _I_c_o_n
        !           192: 
        !           193: 
        !           194: 
        !           195: Version 5.9    The University of Arizona - 5/16/83              3
        !           196: 
        !           197: 
        !           198: 
        !           199: 
        !           200: 
        !           201: 
        !           202: RSG(1)                Icon Program Library                 RSG(1)
        !           203: 
        !           204: 
        !           205: 
        !           206:      _P_r_o_g_r_a_m_m_i_n_g _L_a_n_g_u_a_g_e, Prentice-Hall, Inc., Englewood Cliffs,
        !           207:      New Jersey, 1983.  pp. 211-219, 301-302.
        !           208: 
        !           209:      Wetherell, C. S. ``Probabilistic Languages: A Review and
        !           210:      Some Open Questions'', _C_o_m_p_u_t_e_r _S_u_r_v_e_y_s, Vol. 12, No. 4
        !           211:      (1980), pp. 361-379.
        !           212: 
        !           213: AAAAUUUUTTTTHHHHOOOORRRR
        !           214:      Ralph E. Griswold
        !           215: 
        !           216: 
        !           217: 
        !           218: 
        !           219: 
        !           220: 
        !           221: 
        !           222: 
        !           223: 
        !           224: 
        !           225: 
        !           226: 
        !           227: 
        !           228: 
        !           229: 
        !           230: 
        !           231: 
        !           232: 
        !           233: 
        !           234: 
        !           235: 
        !           236: 
        !           237: 
        !           238: 
        !           239: 
        !           240: 
        !           241: 
        !           242: 
        !           243: 
        !           244: 
        !           245: 
        !           246: 
        !           247: 
        !           248: 
        !           249: 
        !           250: 
        !           251: 
        !           252: 
        !           253: 
        !           254: 
        !           255: 
        !           256: 
        !           257: 
        !           258: 
        !           259: 
        !           260: 
        !           261: Version 5.9    The University of Arizona - 5/16/83              4
        !           262: 
        !           263: 
        !           264: 

This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.