/* Copyright (C) 1995,1996,1997,1998,2000,2001,2003, 2004, 2006 Free Software Foundation, Inc. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #if HAVE_CONFIG_H # include #endif #include "libguile/_scm.h" #include "libguile/ramap.h" #include "libguile/stackchk.h" #include "libguile/strorder.h" #include "libguile/async.h" #include "libguile/root.h" #include "libguile/smob.h" #include "libguile/unif.h" #include "libguile/vectors.h" #include "libguile/struct.h" #include "libguile/goops.h" #include "libguile/objects.h" #include "libguile/validate.h" #include "libguile/eq.h" #ifdef HAVE_STRING_H #include #endif SCM_DEFINE1 (scm_eq_p, "eq?", scm_tc7_rpsubr, (SCM x, SCM y), "Return @code{#t} if @var{x} and @var{y} are the same object,\n" "except for numbers and characters. For example,\n" "\n" "@example\n" "(define x (vector 1 2 3))\n" "(define y (vector 1 2 3))\n" "\n" "(eq? x x) @result{} #t\n" "(eq? x y) @result{} #f\n" "@end example\n" "\n" "Numbers and characters are not equal to any other object, but\n" "the problem is they're not necessarily @code{eq?} to themselves\n" "either. This is even so when the number comes directly from a\n" "variable,\n" "\n" "@example\n" "(let ((n (+ 2 3)))\n" " (eq? n n)) @result{} *unspecified*\n" "@end example\n" "\n" "Generally @code{eqv?} should be used when comparing numbers or\n" "characters. @code{=} or @code{char=?} can be used too.\n" "\n" "It's worth noting that end-of-list @code{()}, @code{#t},\n" "@code{#f}, a symbol of a given name, and a keyword of a given\n" "name, are unique objects. There's just one of each, so for\n" "instance no matter how @code{()} arises in a program, it's the\n" "same object and can be compared with @code{eq?},\n" "\n" "@example\n" "(define x (cdr '(123)))\n" "(define y (cdr '(456)))\n" "(eq? x y) @result{} #t\n" "\n" "(define x (string->symbol \"foo\"))\n" "(eq? x 'foo) @result{} #t\n" "@end example") #define FUNC_NAME s_scm_eq_p { return scm_from_bool (scm_is_eq (x, y)); } #undef FUNC_NAME /* We compare doubles in a special way for 'eqv?' to be able to distinguish plus and minus zero and to identify NaNs. */ static int real_eqv (double x, double y) { return !memcmp (&x, &y, sizeof(double)) || (x != x && y != y); } #include SCM_PRIMITIVE_GENERIC_1 (scm_eqv_p, "eqv?", scm_tc7_rpsubr, (SCM x, SCM y), "Return @code{#t} if @var{x} and @var{y} are the same object, or\n" "for characters and numbers the same value.\n" "\n" "On objects except characters and numbers, @code{eqv?} is the\n" "same as @code{eq?}, it's true if @var{x} and @var{y} are the\n" "same object.\n" "\n" "If @var{x} and @var{y} are numbers or characters, @code{eqv?}\n" "compares their type and value. An exact number is not\n" "@code{eqv?} to an inexact number (even if their value is the\n" "same).\n" "\n" "@example\n" "(eqv? 3 (+ 1 2)) @result{} #t\n" "(eqv? 1 1.0) @result{} #f\n" "@end example") #define FUNC_NAME s_scm_eqv_p { if (scm_is_eq (x, y)) return SCM_BOOL_T; if (SCM_IMP (x)) return SCM_BOOL_F; if (SCM_IMP (y)) return SCM_BOOL_F; /* this ensures that types and scm_length are the same. */ if (SCM_CELL_TYPE (x) != SCM_CELL_TYPE (y)) { /* fractions use 0x10000 as a flag (at the suggestion of Marius Vollmer), but this checks the entire type word, so fractions may be accidentally flagged here as unequal. Perhaps I should use the 4th double_cell word? */ /* treat mixes of real and complex types specially */ if (SCM_INEXACTP (x)) { if (SCM_REALP (x)) return scm_from_bool (SCM_COMPLEXP (y) && real_eqv (SCM_REAL_VALUE (x), SCM_COMPLEX_REAL (y)) && SCM_COMPLEX_IMAG (y) == 0.0); else return scm_from_bool (SCM_REALP (y) && real_eqv (SCM_COMPLEX_REAL (x), SCM_REAL_VALUE (y)) && SCM_COMPLEX_IMAG (x) == 0.0); } if (SCM_FRACTIONP (x) && SCM_FRACTIONP (y)) return scm_i_fraction_equalp (x, y); return SCM_BOOL_F; } if (SCM_NUMP (x)) { if (SCM_BIGP (x)) { return scm_from_bool (scm_i_bigcmp (x, y) == 0); } else if (SCM_REALP (x)) { return scm_from_bool (real_eqv (SCM_REAL_VALUE (x), SCM_REAL_VALUE (y))); } else if (SCM_FRACTIONP (x)) { return scm_i_fraction_equalp (x, y); } else { /* complex */ return scm_from_bool (real_eqv (SCM_COMPLEX_REAL (x), SCM_COMPLEX_REAL (y)) && real_eqv (SCM_COMPLEX_IMAG (x), SCM_COMPLEX_IMAG (y))); } } if (SCM_UNPACK (g_scm_eqv_p)) return scm_call_generic_2 (g_scm_eqv_p, x, y); else return SCM_BOOL_F; } #undef FUNC_NAME SCM_PRIMITIVE_GENERIC_1 (scm_equal_p, "equal?", scm_tc7_rpsubr, (SCM x, SCM y), "Return @code{#t} if @var{x} and @var{y} are the same type, and\n" "their contents or value are equal.\n" "\n" "For a pair, string, vector or array, @code{equal?} compares the\n" "contents, and does so using using the same @code{equal?}\n" "recursively, so a deep structure can be traversed.\n" "\n" "@example\n" "(equal? (list 1 2 3) (list 1 2 3)) @result{} #t\n" "(equal? (list 1 2 3) (vector 1 2 3)) @result{} #f\n" "@end example\n" "\n" "For other objects, @code{equal?} compares as per @code{eqv?},\n" "which means characters and numbers are compared by type and\n" "value (and like @code{eqv?}, exact and inexact numbers are not\n" "@code{equal?}, even if their value is the same).\n" "\n" "@example\n" "(equal? 3 (+ 1 2)) @result{} #t\n" "(equal? 1 1.0) @result{} #f\n" "@end example\n" "\n" "Hash tables are currently only compared as per @code{eq?}, so\n" "two different tables are not @code{equal?}, even if their\n" "contents are the same.\n" "\n" "@code{equal?} does not support circular data structures, it may\n" "go into an infinite loop if asked to compare two circular lists\n" "or similar.\n" "\n" "New application-defined object types (Smobs) have an\n" "@code{equalp} handler which is called by @code{equal?}. This\n" "lets an application traverse the contents or control what is\n" "considered @code{equal?} for two such objects. If there's no\n" "handler, the default is to just compare as per @code{eq?}.") #define FUNC_NAME s_scm_equal_p { SCM_CHECK_STACK; tailrecurse: SCM_TICK; if (scm_is_eq (x, y)) return SCM_BOOL_T; if (SCM_IMP (x)) return SCM_BOOL_F; if (SCM_IMP (y)) return SCM_BOOL_F; if (scm_is_pair (x) && scm_is_pair (y)) { if (scm_is_false (scm_equal_p (SCM_CAR (x), SCM_CAR (y)))) return SCM_BOOL_F; x = SCM_CDR(x); y = SCM_CDR(y); goto tailrecurse; } if (SCM_TYP7 (x) == scm_tc7_string && SCM_TYP7 (y) == scm_tc7_string) return scm_string_equal_p (x, y); if (SCM_TYP7 (x) == scm_tc7_smob && SCM_TYP16 (x) == SCM_TYP16 (y)) { int i = SCM_SMOBNUM (x); if (!(i < scm_numsmob)) return SCM_BOOL_F; if (scm_smobs[i].equalp) return (scm_smobs[i].equalp) (x, y); else goto generic_equal; } /* This ensures that types and scm_length are the same. */ if (SCM_CELL_TYPE (x) != SCM_CELL_TYPE (y)) { /* treat mixes of real and complex types specially */ if (SCM_INEXACTP (x) && SCM_INEXACTP (y)) { if (SCM_REALP (x)) return scm_from_bool (SCM_COMPLEXP (y) && SCM_REAL_VALUE (x) == SCM_COMPLEX_REAL (y) && SCM_COMPLEX_IMAG (y) == 0.0); else return scm_from_bool (SCM_REALP (y) && SCM_COMPLEX_REAL (x) == SCM_REAL_VALUE (y) && SCM_COMPLEX_IMAG (x) == 0.0); } /* Vectors can be equal to one-dimensional arrays. */ if (SCM_I_ARRAYP (x) || SCM_I_ARRAYP (y)) return scm_array_equal_p (x, y); return SCM_BOOL_F; } switch (SCM_TYP7 (x)) { default: break; case scm_tc7_number: switch SCM_TYP16 (x) { case scm_tc16_big: return scm_bigequal (x, y); case scm_tc16_real: return scm_real_equalp (x, y); case scm_tc16_complex: return scm_complex_equalp (x, y); case scm_tc16_fraction: return scm_i_fraction_equalp (x, y); } case scm_tc7_vector: case scm_tc7_wvect: return scm_i_vector_equal_p (x, y); } /* Check equality between structs of equal type (see cell-type test above) that are not GOOPS instances. GOOPS instances are treated via the generic function. */ if ((SCM_STRUCTP (x)) && (!SCM_INSTANCEP (x))) return scm_i_struct_equalp (x, y); generic_equal: if (SCM_UNPACK (g_scm_equal_p)) return scm_call_generic_2 (g_scm_equal_p, x, y); else return SCM_BOOL_F; } #undef FUNC_NAME void scm_init_eq () { #include "libguile/eq.x" } /* Local Variables: c-file-style: "gnu" End: */