From ee99e553f00ed91d4e174dc58c00701a9cbe15d0 Mon Sep 17 00:00:00 2001
From: Timothy Warren <twarren@nabancard.com>
Date: Wed, 4 Oct 2023 14:22:51 -0400
Subject: [PATCH] Highlight string literals

---
 editor/document/row.go        | 40 ++++++++++++++++++++++++++++++++---
 editor/highlight/constants.go |  6 +++++-
 editor/highlight/fn.go        | 20 ------------------
 editor/highlight/syntax.go    | 35 +++++++++++++++++++++++++++---
 4 files changed, 74 insertions(+), 27 deletions(-)
 delete mode 100644 editor/highlight/fn.go

diff --git a/editor/document/row.go b/editor/document/row.go
index 1381359..aa13b57 100644
--- a/editor/document/row.go
+++ b/editor/document/row.go
@@ -112,8 +112,6 @@ func (r *Row) update() {
 func (r *Row) updateSyntax() {
 	i := 0
 	s := r.parent.Syntax
-	prevSep := true
-
 	r.Hl = make([]int, r.RenderSize())
 	for x := range r.Hl {
 		r.Hl[x] = highlight.Normal
@@ -124,6 +122,8 @@ func (r *Row) updateSyntax() {
 		return
 	}
 
+	prevSep := true
+	inString := '0'
 	for i < r.RenderSize() {
 		ch := r.render[i]
 		prevHl := highlight.Normal
@@ -132,7 +132,41 @@ func (r *Row) updateSyntax() {
 			prevHl = r.Hl[i-1]
 		}
 
-		if s.Flags&highlight.HighlightNumbers == 1 {
+		ip1 := i + 1
+
+		if s.Flags&highlight.HighlightStrings == highlight.HighlightStrings {
+			// At the start of a string literal
+			if inString == '0' && (ch == '"' || ch == '\'') {
+				inString = ch
+				r.Hl[i] = highlight.String
+				i++
+				continue
+			}
+
+			// In an existing string
+			if inString != '0' {
+				r.Hl[i] = highlight.String
+
+				// Handle when a quote is escaped inside a string
+				if ch == '\\' && ip1 < r.RenderSize() {
+					r.Hl[ip1] = highlight.String
+					i += 2
+					continue
+				}
+
+				// This quote mark matches the beginning of the string
+				// so now the string is completed
+				if ch == inString {
+					inString = '0'
+				}
+
+				i++
+				prevSep = true
+				continue
+			}
+		}
+
+		if s.Flags&highlight.HighlightNumbers == highlight.HighlightNumbers {
 			if (unicode.IsDigit(ch) && (prevSep || prevHl == highlight.Number)) ||
 				(ch == '.' && prevHl == highlight.Number) {
 				r.Hl[i] = highlight.Number
diff --git a/editor/highlight/constants.go b/editor/highlight/constants.go
index f07a536..92dcf1f 100644
--- a/editor/highlight/constants.go
+++ b/editor/highlight/constants.go
@@ -5,8 +5,12 @@ package highlight
 // ----------------------------------------------------------------------------
 const (
 	Normal = iota
+	String
 	Number
 	Match
 )
 
-const HighlightNumbers = (1 << 0)
+const (
+	HighlightNumbers = 1 << 0
+	HighlightStrings = 1 << 1
+)
diff --git a/editor/highlight/fn.go b/editor/highlight/fn.go
deleted file mode 100644
index 0620c03..0000000
--- a/editor/highlight/fn.go
+++ /dev/null
@@ -1,20 +0,0 @@
-package highlight
-
-import "timshome.page/gilo/terminal"
-
-var syntaxColorMap = map[int]string{
-	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
-}
diff --git a/editor/highlight/syntax.go b/editor/highlight/syntax.go
index b8b6530..dabd12b 100644
--- a/editor/highlight/syntax.go
+++ b/editor/highlight/syntax.go
@@ -1,6 +1,35 @@
 package highlight
 
-import "strings"
+import (
+	"strings"
+	"timshome.page/gilo/terminal"
+)
+
+// ------------------------------------------------------------------
+// Syntax Type -> Color Mapping
+// ------------------------------------------------------------------
+
+var syntaxColorMap = map[int]string{
+	String: terminal.FGMagenta,
+	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
@@ -12,11 +41,11 @@ type Syntax struct {
 var HLDB = []*Syntax{{
 	"c",
 	[]string{".c", ".h", ".cpp"},
-	HighlightNumbers,
+	HighlightNumbers | HighlightStrings,
 }, {
 	"go",
 	[]string{".go", "go.mod"},
-	HighlightNumbers,
+	HighlightNumbers | HighlightStrings,
 }, {
 	"makefile",
 	[]string{"Makefile", "makefile"},