First draft of a Prolog lexer

5 files changed, 86 insertions, 2 deletions

diff --git a/CHANGES b/CHANGES
index a7d5379a..4ba5a8d1 100644
--- a/CHANGES
+++ b/CHANGES
@@ -19,7 +19,8 @@ Version 1.1
 
   * GLSL (#369)
   * Erlang shell
-  * (Ba)sh shell
+  * (Ba)sh shell (#349)
+  * Prolog (#373)
 
 
 Version 1.0
diff --git a/pygments/lexers/_mapping.py b/pygments/lexers/_mapping.py
index 4db345e7..0bbe91bc 100644
--- a/pygments/lexers/_mapping.py
+++ b/pygments/lexers/_mapping.py
@@ -112,6 +112,7 @@ LEXERS = {
     'PerlLexer': ('pygments.lexers.agile', 'Perl', ('perl', 'pl'), ('*.pl', '*.pm'), ('text/x-perl', 'application/x-perl')),
     'PhpLexer': ('pygments.lexers.web', 'PHP', ('php', 'php3', 'php4', 'php5'), ('*.php', '*.php[345]'), ('text/x-php',)),
     'PovrayLexer': ('pygments.lexers.other', 'POVRay', ('pov',), ('*.pov', '*.inc'), ('text/x-povray',)),
+    'PrologLexer': ('pygments.lexers.compiled', 'prolog', ('plog',), ('*.prolog', '*.pro'), ('text/x-prolog',)),
     'Python3Lexer': ('pygments.lexers.agile', 'Python 3', ('python3', 'py3'), (), ('text/x-python3', 'application/x-python3')),
     'Python3TracebackLexer': ('pygments.lexers.agile', 'Python 3.0 Traceback', ('py3tb',), ('*.py3tb',), ('text/x-python3-traceback',)),
     'PythonConsoleLexer': ('pygments.lexers.agile', 'Python console session', ('pycon',), (), ('text/x-python-doctest',)),
diff --git a/pygments/lexers/compiled.py b/pygments/lexers/compiled.py
index 525c84b0..cd96c1fa 100644
--- a/pygments/lexers/compiled.py
+++ b/pygments/lexers/compiled.py
@@ -29,7 +29,7 @@ from pygments.lexers.functional import OcamlLexer
 
 __all__ = ['CLexer', 'CppLexer', 'DLexer', 'DelphiLexer', 'JavaLexer', 'ScalaLexer',
            'DylanLexer', 'OcamlLexer', 'ObjectiveCLexer', 'FortranLexer',
-           'GLShaderLexer']
+           'GLShaderLexer', 'PrologLexer']
 
 
 class CLexer(RegexLexer):
@@ -1330,3 +1330,53 @@ class GLShaderLexer(RegexLexer):
             (r'\s+', Text),
         ],
     }
+
+class PrologLexer(RegexLexer):
+    name = 'prolog'
+    aliases = ['plog']
+    filenames = ['*.prolog', '*.pro']
+    mimetypes = ['text/x-prolog']
+
+    flags = re.UNICODE
+
+    tokens = {
+        'root': [
+            (r'^#.*', Comment),
+            (r'/\*', Comment, 'nested-comment'),
+            (r'%.*', Comment),
+            (r'[0-9]+', Number),
+            (r'[\[\](){}|.,;!]', Punctuation),
+            (r':-|-->', Punctuation),
+            (r'"(?:\\x[0-9a-fA-F]+\\|\\u[0-9a-fA-F]{4}|\U[0-9a-fA-F]{8}|'
+             r'\\[0-7]+\\|\\[\w\W]|[^"]+)*"', String.Double),
+            (r"'(?:''|[^']+)*'", String.Atom), # quoted atom
+            # Needs to not be followed by an atom.
+            #(r'=(?=\s|[a-zA-Z\[])', Operator),
+            (r'(is|<|>|=<|>=|==|=:=|=|/|//|\*|\+|-)(?=\s|[a-zA-Z0-9\[])', Operator),
+            (r'(mod|div|not)\b', Operator),
+            (r'_', Keyword), # The don't-care variable
+            (r'([a-z]+)(:)', bygroups(Name.Namespace, Punctuation)),
+            (ur'([a-z\u00c0-\u1fff\u3040-\ud7ff\ue000-\uffef]'
+             ur'[a-zA-Z0-9_$\u00c0-\u1fff\u3040-\ud7ff\ue000-\uffef]*)'
+             ur'(\s*)(:-|-->)',
+             bygroups(Name.Function, Text, Operator)), # function defn
+            (ur'([a-z\u00c0-\u1fff\u3040-\ud7ff\ue000-\uffef]'
+             ur'[a-zA-Z0-9_$\u00c0-\u1fff\u3040-\ud7ff\ue000-\uffef]*)'
+             ur'(\s*)(\()',
+             bygroups(Name.Function, Text, Punctuation)),
+            (ur'[a-z\u00c0-\u1fff\u3040-\ud7ff\ue000-\uffef]'
+             ur'[a-zA-Z0-9_$\u00c0-\u1fff\u3040-\ud7ff\ue000-\uffef]*',
+             String.Atom), # atom, characters
+            # This one includes !
+            (ur'[#&*+\-./:<=>?@\\^~\u00a1-\u00bf\u2010-\u303f]+',
+             String.Atom), # atom, graphics
+            (r'[A-Z_][A-Za-z0-9]*', Name.Variable),
+            (u'\s+|[\u2000-\u200f\ufff0-\ufffe\uffef]', Text),
+        ],
+        'nested-comment': [
+            (r'\*/', Comment, '#pop'),
+            (r'/\*', Comment, '#push'),
+            (r'[^*/]+', Comment),
+            (r'[*/]', Comment),
+        ],
+    }
diff --git a/tests/examplefiles/qsort.prolog b/tests/examplefiles/qsort.prolog
new file mode 100644
index 00000000..d78de6f1
--- /dev/null
+++ b/tests/examplefiles/qsort.prolog
@@ -0,0 +1,13 @@
+partition([], _, [], []).
+partition([X|Xs], Pivot, Smalls, Bigs) :-
+    (   X @< Pivot ->
+        Smalls = [X|Rest],
+        partition(Xs, Pivot, Rest, Bigs)
+    ;   Bigs = [X|Rest],
+        partition(Xs, Pivot, Smalls, Rest)
+    ).
+
+quicksort([])     --> [].
+quicksort([X|Xs]) --> 
+    { partition(Xs, X, Smaller, Bigger) },
+    quicksort(Smaller), [X], quicksort(Bigger).
diff --git a/tests/examplefiles/sibling.prolog b/tests/examplefiles/sibling.prolog
new file mode 100644
index 00000000..bc591502
--- /dev/null
+++ b/tests/examplefiles/sibling.prolog
@@ -0,0 +1,19 @@
+/* Comments /* can nest */
+still a comment
+*/
+
+:- module(maplist, maplist/3)
+
+assert(world:done). % asserts
+
+sibling(X, Y)      :- parent_child(Z, X), parent_child(Z, Y).
+
+parent_child(X, Y) :- father_child(X, Y).
+parent_child(X, Y) :- mother_child(X, Y).
+
+mother_child(trude, sally).
+
+father_child(tom, sally).
+father_child(tom, erica).
+father_child(mike, tom).
+