gilo/editor/highlight/highlight.go

package highlight

import (
	"strings"
	"timshome.page/gilo/terminal"
)

// ----------------------------------------------------------------------------
// !Syntax Highlighting Constants
// ----------------------------------------------------------------------------
const (
	Normal = iota
	Comment
	Keyword1
	Keyword2
	String
	Number
	Match
)

const (
	DoNumbers = 1 << 0
	DoStrings = 1 << 1
)

// ------------------------------------------------------------------
// Syntax Type -> Color Mapping
// ------------------------------------------------------------------

var syntaxColorMap = map[int]string{
	Comment:  terminal.FGCyan,
	Keyword1: terminal.FGYellow,
	Keyword2: terminal.FGGreen,
	String:   terminal.FGBrightMagenta,
	Number:   terminal.FGRed,
	Match:    terminal.FGBlue,
	Normal:   terminal.DefaultFGColor,
}

// SyntaxToColor Take a highlighting type and map it to
// an ANSI color escape code for display
func SyntaxToColor(hl int) string {
	color := syntaxColorMap[hl]
	if len(color) == 0 {
		color = terminal.DefaultFGColor
	}

	return color
}

// ------------------------------------------------------------------
// File Type -> Syntax Mapping
// ------------------------------------------------------------------

type Syntax struct {
	FileType         string
	FileMatch        []string
	LineCommentStart string
	Keywords1        []string
	Keywords2        []string
	Flags            int
}

// HLDB - The "database" of syntax types
var HLDB = []*Syntax{{
	"c",
	[]string{".c", ".h", ".cpp"},
	"//",
	[]string{"switch", "if", "while", "for", "break", "continue", "return", "else", "struct", "union", "typedef", "static", "enum", "class", "case"},
	[]string{"int", "long", "double", "float", "char", "unsigned", "signed", "void"},
	DoNumbers | DoStrings,
}, {
	"go",
	[]string{".go", "go.mod"},
	"//",
	[]string{"break", "case", "chan", "const", "continue", "default", "defer", "else", "fallthrough", "for", "func", "go", "goto", "if", "import", "interface", "map", "package", "range", "return", "select", "struct", "switch", "type", "var", "iota"},
	[]string{"bool", "uint8", "uint16", "uint32", "uint64", "int8", "int16", "int32", "int64", "float32", "float64", "complex64", "complex128", "byte", "rune", "uint", "int", "uintptr", "string", "struct", "type", "map"},
	DoNumbers | DoStrings,
}, {
	"makefile",
	[]string{"Makefile", "makefile", "justfile"},
	"#",
	[]string{},
	[]string{},
	0,
}}

func GetSyntaxByFilename(filename string) *Syntax {
	if filename == "" {
		return nil
	}

	var ext string = ""
	extInd := strings.LastIndex(filename, ".")
	if extInd > -1 {
		ext = filename[extInd:len(filename)]
	}

	for i := 0; i < len(HLDB); i++ {
		s := HLDB[i]
		for j := range s.FileMatch {
			if s.FileMatch[j] == ext || strings.Contains(filename, s.FileMatch[j]) {
				return s
			}
		}
	}

	return nil
}