Literal '_' in prolog?
Is there a way to unify to the quoted atom '_' as the literal underscore? Or does Prolog still treat this as the anonymous variable? I cannot for the life of me get a functor(['_']) to fire even if I type that exact phrase into the prolog prompt.
This is part of a larger program where I'm taking a string input as a list of ASCII codes, then to a list of atoms, and finally trying to do some list processing on that. I'm currently using the combo of read_line_to_codes/2, name/2 atom_chars/2. to obtain that list of atoms.
Please excuse any improper terminology; I'm new to Prolog.
prolog
edited Nov 18 '18 at 21:42
false
10.4k773151
asked Nov 16 '18 at 3:52
BrandonBrandon
165
add a comment |
Is there a way to unify to the quoted atom '_' as the literal underscore? Or does Prolog still treat this as the anonymous variable? I cannot for the life of me get a functor(['_']) to fire even if I type that exact phrase into the prolog prompt.
This is part of a larger program where I'm taking a string input as a list of ASCII codes, then to a list of atoms, and finally trying to do some list processing on that. I'm currently using the combo of read_line_to_codes/2, name/2 atom_chars/2. to obtain that list of atoms.
Please excuse any improper terminology; I'm new to Prolog.
prolog
edited Nov 18 '18 at 21:42
false
10.4k773151
asked Nov 16 '18 at 3:52
BrandonBrandon
165
1
That is a literal underscore. However, you're reading codes, not chars, so you probably want 95 instead.
– Daniel Lyons
Nov 16 '18 at 6:39
1
To underscore (no pun intended) what Daniel said:atom_codes('_', C).results inC = [95].atom_chars/2just breaks an atom up into a list of single-character atoms, not atom character codes.
– lurker
Nov 16 '18 at 14:33
add a comment |
Is there a way to unify to the quoted atom '_' as the literal underscore? Or does Prolog still treat this as the anonymous variable? I cannot for the life of me get a functor(['_']) to fire even if I type that exact phrase into the prolog prompt.
This is part of a larger program where I'm taking a string input as a list of ASCII codes, then to a list of atoms, and finally trying to do some list processing on that. I'm currently using the combo of read_line_to_codes/2, name/2 atom_chars/2. to obtain that list of atoms.
Please excuse any improper terminology; I'm new to Prolog.
prolog
edited Nov 18 '18 at 21:42
false
10.4k773151
asked Nov 16 '18 at 3:52
BrandonBrandon
165
Is there a way to unify to the quoted atom '_' as the literal underscore? Or does Prolog still treat this as the anonymous variable? I cannot for the life of me get a functor(['_']) to fire even if I type that exact phrase into the prolog prompt.
This is part of a larger program where I'm taking a string input as a list of ASCII codes, then to a list of atoms, and finally trying to do some list processing on that. I'm currently using the combo of read_line_to_codes/2, name/2 atom_chars/2. to obtain that list of atoms.
Please excuse any improper terminology; I'm new to Prolog.
prolog
prolog
edited Nov 18 '18 at 21:42
false
10.4k773151
asked Nov 16 '18 at 3:52
BrandonBrandon
165
edited Nov 18 '18 at 21:42
false
10.4k773151
asked Nov 16 '18 at 3:52
BrandonBrandon
165
edited Nov 18 '18 at 21:42
false
10.4k773151
edited Nov 18 '18 at 21:42
false
10.4k773151
edited Nov 18 '18 at 21:42
false
10.4k773151
10.4k773151
asked Nov 16 '18 at 3:52
BrandonBrandon
165
asked Nov 16 '18 at 3:52
BrandonBrandon
165
asked Nov 16 '18 at 3:52
BrandonBrandon
165
165
1
That is a literal underscore. However, you're reading codes, not chars, so you probably want 95 instead.
– Daniel Lyons
Nov 16 '18 at 6:39
1
To underscore (no pun intended) what Daniel said:atom_codes('_', C).results inC = [95].atom_chars/2just breaks an atom up into a list of single-character atoms, not atom character codes.
– lurker
Nov 16 '18 at 14:33
add a comment |
1
That is a literal underscore. However, you're reading codes, not chars, so you probably want 95 instead.
– Daniel Lyons
Nov 16 '18 at 6:39
1
To underscore (no pun intended) what Daniel said:atom_codes('_', C).results inC = [95].atom_chars/2just breaks an atom up into a list of single-character atoms, not atom character codes.
– lurker
Nov 16 '18 at 14:33
1
1
That is a literal underscore. However, you're reading codes, not chars, so you probably want 95 instead.
– Daniel Lyons
Nov 16 '18 at 6:39
That is a literal underscore. However, you're reading codes, not chars, so you probably want 95 instead.
– Daniel Lyons
Nov 16 '18 at 6:39
1
1
To underscore (no pun intended) what Daniel said:
atom_codes('_', C). results in C = [95]. atom_chars/2 just breaks an atom up into a list of single-character atoms, not atom character codes.– lurker
Nov 16 '18 at 14:33
To underscore (no pun intended) what Daniel said:
atom_codes('_', C). results in C = [95]. atom_chars/2 just breaks an atom up into a list of single-character atoms, not atom character codes.– lurker
Nov 16 '18 at 14:33
add a comment |
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1
That is a literal underscore. However, you're reading codes, not chars, so you probably want 95 instead.
– Daniel Lyons
Nov 16 '18 at 6:39
1
To underscore (no pun intended) what Daniel said:
atom_codes('_', C).results inC = [95].atom_chars/2just breaks an atom up into a list of single-character atoms, not atom character codes.– lurker
Nov 16 '18 at 14:33