Add FortranFixedLexer

Author: ProgramFan

Diff for: lexers/f/fortran_fixed.go

@@ -0,0 +1,39 @@
+package f
+
+import (
+	. "github.com/alecthomas/chroma" // nolint
+	"github.com/alecthomas/chroma/lexers/internal"
+)
+
+// FortranFixed lexer.
+var FortranFixed = internal.Register(MustNewLazyLexer(
+	&Config{
+		Name:            "FortranFixed",
+		Aliases:         []string{"fortranfixed"},
+		Filenames:       []string{"*.f", "*.F"},
+		MimeTypes:       []string{"text/x-fortran"},
+		NotMultiline:    true,
+		CaseInsensitive: true,
+	},
+	func() Rules {
+		return Rules{
+			"root": {
+				{`[C*].*\n`, Comment, nil},
+				{`#.*\n`, CommentPreproc, nil},
+				{`[\t ]*!.*\n`, Comment, nil},
+				{`(.{5})`, NameLabel, Push("cont-char")},
+				{`.*\n`, Using(Fortran), nil},
+			},
+			"cont-char": {
+				{` `, Text, Push("code")},
+				{`0`, Comment, Push("code")},
+				{`.`, GenericStrong, Push("code")},
+			},
+			"code": {
+				{`(.{66})(.*)(\n)`, ByGroups(Using(Fortran), Comment, Text), Push("root")},
+				{`.*\n`, Using(Fortran), Push("root")},
+				Default(Push("root")),
+			},
+		}
+	},
+))