Adds support for backtick escaping in a raw string

README.md

@@ -58,8 +58,9 @@ slope recognizes a few types, that are generally created and used dynamically:
   - as `#t` and `#f`
   - anything can be cast to bool with a `#t` value, except `#f` (the only truly falsy value without using `~bool`, see below)
 - `string`
-  - anything in "quotes"
-  - allows for backslash escapes within the quotes (for chars by number or shortcuts to tab, newline, etc)
+  - anything in "quotes" is a standard string literal
+    - allows for backslash escapes within the quotes (for chars by number or shortcuts to tab, newline, etc)
+  - anything in `backticks` is a raw string literal, no escapes occur and strings can span multiple lines
 - `list`/`pair`
   - includes the empty list (null)
   - lists are the primary data structure

helpers.go

@@ -542,20 +542,29 @@ func createTimeFormatString(s string) string {
 
 // Used by REPL to know if another input line
 // should be offered before parsing
-func stringParensMatch(s string) bool {
+func stringParensMatch(s string) (bool, bool) {
 	count := 0
 	inString := false
 	prevPrev := rune(0)
+	inrawString := false
 	prev := ' '
 
 	for _, c := range s {
 		switch c {
 		case '(':
-			if !inString && prev != '\'' {
+			if !inString && !inrawString && prev != '\'' {
 				count++
 			}
 		case ')':
-			if !inString {
+			if !inString && !inrawString {
+				count--
+			}
+		case '`':
+			if !inrawString {
+				inrawString = true
+				count++
+			} else if prev != '\\' || (prev == '\\' && prevPrev == '\\') {
+				inrawString = false
 				count--
 			}
 		case '"':
@@ -570,12 +579,12 @@ func stringParensMatch(s string) bool {
 	}
 
 	if count > 0 {
-		return false
+		return false, inrawString
 	}
 
 	// If count is negative still return true, the
 	// parser will handle erroring
-	return true
+	return true, inrawString
 }
 
 func variadic(l []expression) int {

interpreter.go

@@ -548,6 +548,8 @@ func eval(exp expression, en *env) (value expression) {
 			}
 			var text strings.Builder
 			var cont bool
+			var raw bool
+			var match bool
 			for {
 				globalenv.vars[symbol("slope-interactive?")] = true
 				if linerState != nil {
@@ -560,12 +562,14 @@ func eval(exp expression, en *env) (value expression) {
 				if in == "uninspect" || in == "(uninspect)" {
 					break
 				}
-				if len(strings.TrimSpace(in)) == 0 {
+				if len(strings.TrimSpace(in)) == 0 && !raw {
 					continue
 				}
 				text.WriteString(in)
 				text.WriteRune('\n')
-				if !stringParensMatch(text.String()) {
+
+				match, raw = stringParensMatch(text.String())
+				if !match {
 					cont = true
 				} else {
 					cont = false

lexer.go

@@ -47,11 +47,17 @@ func eatString(r *strings.Reader, delim rune) string {
 		if err != nil {
 			panic("Lexing error while eating string")
 		}
-		buf.WriteRune(c)
+		if delim == '`' && c == delim && (escapeCount > 0 && escapeCount%2 != 0) {
+			out := buf.String()
+			buf.Reset()
+			buf.WriteString(out[:len(out)-1])
+			buf.WriteRune(c)
+		} else {
+			buf.WriteRune(c)
+		}
 		if c == delim && (escapeCount == 0 || escapeCount%2 == 0) {
 			break
-		} else if c == '\n' || (c != delim && r.Len() == 0) {
-			fmt.Println(delim, c, r.Len())
+		} else if (delim == '"' && c == '\n') || (c != delim && r.Len() == 0) {
 			panic(fmt.Sprintf("Parse error: Unclosed string on line %d ", lexLine))
 		}
 		if c == '\\' {

main.go

@@ -141,6 +141,8 @@ func Repl() {
 
 	var text strings.Builder
 	var cont bool
+	var raw bool
+	var match bool
 	for {
 		globalenv.vars[symbol("slope-interactive?")] = true
 		if linerTerm != nil {
@@ -150,12 +152,14 @@ func Repl() {
 		if initialTerm != nil {
 			initialTerm.ApplyMode()
 		}
-		if len(strings.TrimSpace(in)) == 0 {
+		if len(strings.TrimSpace(in)) == 0 && !raw {
 			continue
 		}
 		text.WriteString(in)
 		text.WriteRune('\n')
-		if !stringParensMatch(text.String()) {
+
+		match, raw = stringParensMatch(text.String())
+		if !match {
 			cont = true
 		} else {
 			cont = false