Crystal syntax highlighting for the nano editor

crystal.nanorc

## Syntax highlighting for Crystal.

syntax crystal "\.cr$"

comment "#"
tabgives "  "


# Constants.
color brightblue "\<[A-Z]+[0-9A-Z_a-z]*|(\$|@|@@)[0-9A-Z_a-z]+"

# Operators
color red "(\|\||&[&*+-]?|[!?]|[=!*/+-]=|=>|[><]=?|=(==)?|[*/^+-])"

# Reserved keywords (Language)
color yellow "\<(require|alias|end)\>"
color yellow "\<(true|false|nil)\>"

color yellow "\<(abstract|private|module|class|struct|include|extend)\>"
color yellow "\<(class_)?(setter|(getter|property)[!?]?)"
color yellow "\<(new|self|super|finalize)\>"

color yellow "\<((previous_|un)?def|yield|return)\>"
color yellow "\<(if|unless|elsif|else)\>"
color yellow "\<(case|when|in|then)\>"
color yellow "\<(do|while|until|break|next)\>"
color yellow "\<(begin|rescue|ensure)\>"

# Reserved keywords (Top level namespace & Crystal macros)
color yellow "\<(abort|at_exit|caller|exit|loop|main|raise|sleep|spawn)\>"
color yellow "\<(gets|puts|read_line|pp?!?|s?printf?)\>"
color yellow "\<((host_)?flag[?]|parse_type|(instance_)?sizeof|offsetof|pointerof|typeof)\>"
color yellow "\<(compare_versions|debug|env|rand|run|system|timeout_select_action)\>"
color yellow "\<(file_exists[?]|read_file[?]?|skip_file)\>"


# "do" parameters
color red "\|\w+(,\s*\w+)*\|"

# Numbers
color blue "\b0([xX][A-Fa-f0-9_]+|[bB][01]+|o[0-7]+)(_(u8|u16|u32|u64|i8|i16|i32|i64|f32|f64))?\b"
color blue "\b[0-9][0-9_]*(\.[0-9][0-9_]*)?([eE][-+]?[0-9][0-9_]*)?(_(u8|u16|u32|u64|i8|i16|i32|i64|f32|f64))?\b"


# Common object methods
#color brightcyan "\<()\>"
color brightcyan "\<(nil[?]|not_nil!|class|dup|(pretty_)?inspect|parse|responds_to[?]|try)"
color brightcyan "\<(each(_(with_index|slice|key|value))?|reject!?|select|(compact_)?map|skip(_while)?|uniq)"

color brightcyan "\<(as_[afhius][?]?|as_bool|as_(f32|i64)[?]?|as_nil|as|is_a[?])"
color brightcyan "\<(clone|compact!?|delete|dig[?]?|dup|inspect|merge!?|raw|size)"

color brightcyan "\<(to_(json|xml|s)|to_[iu](8|16|128)[!?]?|to_[ifu](32|64)?[!?]?|to_big_[dfi])"
color brightcyan "\<(delete(_at)?|empty[?]|(starts|ends)_with[?]|reverse!?|split|g?sub)"

color brightcyan "\<(abs|ceil|fdiv|floor|round|trunc)\>"


# Ruby "symbols".
color magenta "([ 	]|^):[0-9A-Za-z_]+\>"
color magenta "\<([0-9A-Za-z_]+\:)\>"

# Some unique things we want to stand out.
#color brightyellow "\<(__FILE__|__LINE__)\>"

# Regular expressions.
color brightmagenta "/([^/]|(\\/))*/[iomx]*" "%r\{([^}]|(\\}))*\}[iomx]*"

# Shell command expansion is in `backticks` or like %x{this}.  These are
# "double-quotish" (to use a perlism).
color brightblue "`[^`]*`" "%x\{[^}]*\}"

# Strings, double-quoted.
color green ""([^"]|(\\"))*"" "%[QW]?\{[^}]*\}" "%[QW]?\([^)]*\)" "%[QW]?<[^>]*>" "%[QW]?\[[^]]*\]" "%[QW]?\$[^$]*\$" "%[QW]?\^[^^]*\^" "%[QW]?![^!]*!"
# Expression substitution.  These go inside double-quoted strings, "like #{this}".
color brightgreen "#\{[^}]*\}"
# Strings, single-quoted.
color green "'([^']|(\\'))*'" "%[qw]\{[^}]*\}" "%[qw]\([^)]*\)" "%[qw]<[^>]*>" "%[qw]\[[^]]*\]" "%[qw]\$[^$]*\$" "%[qw]\^[^^]*\^" "%[qw]![^!]*!"

# Comments.
color cyan "#[^{].*" "#$"
color brightcyan "##[^{].*" "##$"

# "Here" docs.
color green start="<<-?'?EOT'?" end="^EOT"

# Some common markers.
color brightcyan "XXX|TODO|FIXME|\?\?\?"