1:- module(lambda, [ 2 (^)/3, (^)/4, (^)/5, (^)/6, (^)/7, (^)/8, (^)/9, 3 (\)/1, (\)/2, (\)/3, (\)/4, (\)/5, (\)/6, (\)/7, 4 (+\)/2, (+\)/3, (+\)/4, (+\)/5, (+\)/6, (+\)/7, 5 op(201,xfx,+\)], eclipse_language). 6 7:- export initialization( 8 ( 9 current_module_predicate(exported,P)@lambda, 10 \+current_predicate(P), 11 (import P from lambda), 12 printf(warning_output, "WARNING: library(lambda) redefines %Dw%n", [P]), 13 fail 14 ; 15 true 16 )). 17:- local op(1150,fx,meta_predicate). 18 19:- comment(categories, ["Programming Utilities"]). 20:- comment(author, "Ulrich Neumerkel, ulrich@complang.tuwien.ac.at (ECLiPSe port: Joachim Schimpf)"). 21:- comment(copyright, "2009 Ulrich Neumerkel. All rights reserved. 22 23Redistribution and use in source and binary forms, with or without 24modification, are permitted provided that the following conditions are 25met: 26 271. Redistributions of source code must retain the above copyright 28 notice, this list of conditions and the following disclaimer. 29 302. Redistributions in binary form must reproduce the above copyright 31 notice, this list of conditions and the following disclaimer in the 32 documentation and/or other materials provided with the distribution. 33 34THIS SOFTWARE IS PROVIDED BY Ulrich Neumerkel ``AS IS'' AND ANY 35EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 36IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 37PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL Ulrich Neumerkel OR 38CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 39EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 40PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 41PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 42LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 43NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 44SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 45 46The views and conclusions contained in the software and documentation 47are those of the authors and should not be interpreted as representing 48official policies, either expressed or implied, of Ulrich Neumerkel. 49"). 50 51:- comment(summary, "This library provides lambda expressions to simplify higher order 52programming based on call/N."). 53 54:- comment(desc, html("<PRE> 55/** <module> Lambda expressions 56 57This library provides lambda expressions to simplify higher order 58programming based on call/N. 59 60Lambda expressions are represented by ordinary Prolog terms. 61There are two kinds of lambda expressions: 62 63 Free+\\X1^X2^ ..^XN^Goal 64 65 \\X1^X2^ ..^XN^Goal 66 67The second is a shorthand for t+\\X1^X2^..^XN^Goal. 68 69Xi are the parameters. 70 71Goal is a goal or continuation. Syntax note: Operators within Goal 72require parentheses due to the low precedence of the ^ operator. 73 74Free contains variables that are valid outside the scope of the lambda 75expression. They are thus free variables within. 76 77All other variables of Goal are considered local variables. They must 78not appear outside the lambda expression. This restriction is 79currently not checked. Violations may lead to unexpected bindings. 80 81In the following example the parentheses around X>3 are necessary. 82 83== 84?- use_module(library(lambda)). 85?- use_module(library(apply)). 86 87?- maplist(\\X^(X>3),[4,5,9]). 88true. 89== 90 91In the following X is a variable that is shared by both instances of 92the lambda expression. The second query illustrates the cooperation of 93continuations and lambdas. The lambda expression is in this case a 94continuation expecting a further argument. 95 96== 97?- Xs = [A,B], maplist(X+\\Y^dif(X,Y), Xs). 98Xs = [A, B], 99dif(X, A), 100dif(X, B). 101 102?- Xs = [A,B], maplist(X+\\dif(X), Xs). 103Xs = [A, B], 104dif(X, A), 105dif(X, B). 106== 107 108The following queries are all equivalent. To see this, use 109the fact f(x,y). 110== 111?- call(f,A1,A2). 112?- call(\\X^f(X),A1,A2). 113?- call(\\X^Y^f(X,Y), A1,A2). 114?- call(\\X^(X+\\Y^f(X,Y)), A1,A2). 115?- call(call(f, A1),A2). 116?- call(f(A1),A2). 117?- f(A1,A2). 118A1 = x, 119A2 = y. 120== 121 122Further discussions 123http://www.complang.tuwien.ac.at/ulrich/Prolog-inedit/ISO-Hiord 124 125@tbd Static expansion similar to apply_macros. 126@author Ulrich Neumerkel 127*/ 128</PRE>")). 129 130:- meta_predicate no_hat_call(0). 131:- tool(no_hat_call/1, no_hat_call_/2). 132 133:- meta_predicate 134 ^(?,0,?), 135 ^(?,1,?,?), 136 ^(?,2,?,?,?), 137 ^(?,3,?,?,?,?), 138 ^(?,4,?,?,?,?,?), 139 ^(?,5,?,?,?,?,?,?), 140 ^(?,6,?,?,?,?,?,?,?). 141:- tool((^)/3, '^_'/4). 142:- tool((^)/4, '^_'/5). 143:- tool((^)/5, '^_'/6). 144:- tool((^)/6, '^_'/7). 145:- tool((^)/7, '^_'/8). 146:- tool((^)/8, '^_'/9). 147:- tool((^)/9, '^_'/10). 148 149'^_'(V1,Goal,V1,M) :- 150 no_hat_call(Goal)@M. 151'^_'(V1,Goal,V1,V2,M) :- 152 call(Goal,V2)@M. 153'^_'(V1,Goal,V1,V2,V3,M) :- 154 call(Goal,V2,V3)@M. 155'^_'(V1,Goal,V1,V2,V3,V4,M) :- 156 call(Goal,V2,V3,V4)@M. 157'^_'(V1,Goal,V1,V2,V3,V4,V5,M) :- 158 call(Goal,V2,V3,V4,V5)@M. 159'^_'(V1,Goal,V1,V2,V3,V4,V5,V6,M) :- 160 call(Goal,V2,V3,V4,V5,V6)@M. 161'^_'(V1,Goal,V1,V2,V3,V4,V5,V6,V7,M) :- 162 call(Goal,V2,V3,V4,V5,V6,V7)@M. 163 164:- meta_predicate 165 \(0), 166 \(1,?), 167 \(2,?,?), 168 \(3,?,?,?), 169 \(4,?,?,?,?), 170 \(5,?,?,?,?,?), 171 \(6,?,?,?,?,?,?). 172:- tool((\)/1, '\\_'/2). 173:- tool((\)/2, '\\_'/3). 174:- tool((\)/3, '\\_'/4). 175:- tool((\)/4, '\\_'/5). 176:- tool((\)/5, '\\_'/6). 177:- tool((\)/6, '\\_'/7). 178:- tool((\)/7, '\\_'/8). 179 180'\\_'(FC,M) :- 181 copy_term(FC,C,_),no_hat_call(C)@M. 182'\\_'(FC,V1,M) :- 183 copy_term(FC,C,_),call(C,V1)@M. 184'\\_'(FC,V1,V2,M) :- 185 copy_term(FC,C,_),call(C,V1,V2)@M. 186'\\_'(FC,V1,V2,V3,M) :- 187 copy_term(FC,C,_),call(C,V1,V2,V3)@M. 188'\\_'(FC,V1,V2,V3,V4,M) :- 189 copy_term(FC,C,_),call(C,V1,V2,V3,V4)@M. 190'\\_'(FC,V1,V2,V3,V4,V5,M) :- 191 copy_term(FC,C,_),call(C,V1,V2,V3,V4,V5)@M. 192'\\_'(FC,V1,V2,V3,V4,V5,V6,M) :- 193 copy_term(FC,C,_),call(C,V1,V2,V3,V4,V5,V6)@M. 194 195:- meta_predicate 196 +\(?,0), 197 +\(?,1,?), 198 +\(?,2,?,?), 199 +\(?,3,?,?,?), 200 +\(?,4,?,?,?,?), 201 +\(?,5,?,?,?,?,?), 202 +\(?,6,?,?,?,?,?,?). 203:- tool((+\)/2, '+\\_'/3). 204:- tool((+\)/3, '+\\_'/4). 205:- tool((+\)/4, '+\\_'/5). 206:- tool((+\)/5, '+\\_'/6). 207:- tool((+\)/6, '+\\_'/7). 208:- tool((+\)/7, '+\\_'/8). 209:- tool((+\)/8, '+\\_'/9). 210 211'+\\_'(GV,FC,M) :- 212 copy_term(GV+FC,GV+C,_),no_hat_call(C)@M. 213'+\\_'(GV,FC,V1,M) :- 214 copy_term(GV+FC,GV+C,_),call(C,V1)@M. 215'+\\_'(GV,FC,V1,V2,M) :- 216 copy_term(GV+FC,GV+C,_),call(C,V1,V2)@M. 217'+\\_'(GV,FC,V1,V2,V3,M) :- 218 copy_term(GV+FC,GV+C,_),call(C,V1,V2,V3)@M. 219'+\\_'(GV,FC,V1,V2,V3,V4,M) :- 220 copy_term(GV+FC,GV+C,_),call(C,V1,V2,V3,V4)@M. 221'+\\_'(GV,FC,V1,V2,V3,V4,V5,M) :- 222 copy_term(GV+FC,GV+C,_),call(C,V1,V2,V3,V4,V5)@M. 223'+\\_'(GV,FC,V1,V2,V3,V4,V5,V6,M) :- 224 copy_term(GV+FC,GV+C,_),call(C,V1,V2,V3,V4,V5,V6)@M. 225 226 227%% no_hat_call(:Goal) 228% 229% Like call, but issues an error for a goal (^)/2. Such goals are 230% likely the result of an insufficient number of arguments. 231 232no_hat_call_(Goal, M) :- 233 ( nonvar(Goal), 234 Goal = (_^_) 235 -> throw(error(existence_error(lambda_parameters,Goal),_)) 236 ; call(Goal)@M 237 ). 238 239% I would like to replace this by: 240% V1^Goal :- throw(error(existence_error(lambda_parameters,V1^Goal),_)). 241