From 8dbc479804a6477f84144ccbea6537c2068e666c Mon Sep 17 00:00:00 2001
From: Arpad Ryszka <arpad.ryszka@gmail.com>
Date: Sun, 29 Oct 2017 01:14:31 +0200
Subject: [PATCH] automatic whitespace for eskip

---
 eskip.parser  | 49 +++++++++++++++++++++----------------------------
 sexpr_test.go | 26 ++++++++++++++++++++++++++
 whitespace.go |  7 +++++--
 3 files changed, 52 insertions(+), 30 deletions(-)

diff --git a/eskip.parser b/eskip.parser
index 541a577..3a6cdcf 100644
--- a/eskip.parser
+++ b/eskip.parser
@@ -2,56 +2,49 @@
 Eskip routing configuration format for Skipper: https://github.com/zalando/skipper
 */
 
-// TODO: definition with comment, doc = comment, or just replace comment
-
 eskip:root = (expression | definitions)?;
 
-comment-line:alias = "//" [^\n]*;
-space:alias        = [ \b\f\r\t\v];
-comment:alias      = comment-line (space* "\n" space* comment-line)*;
-
-wsc:alias = [ \b\f\n\r\t\v] | comment;
+space:ws   = [ \n\b\f\r\t\v];
+comment:ws = "//" [^\n]*;
 
 decimal-digit:alias = [0-9];
 octal-digit:alias   = [0-7];
 hexa-digit:alias    = [0-9a-fA-F];
 
-decimal:alias = [1-9] decimal-digit*;
-octal:alias   = "0" octal-digit*;
-hexa:alias    = "0" [xX] hexa-digit+;
-int           = decimal | octal | hexa;
+decimal:alias:nows = [1-9] decimal-digit*;
+octal:alias:nows   = "0" octal-digit*;
+hexa:alias:nows    = "0" [xX] hexa-digit+;
+int                = decimal | octal | hexa;
 
-exponent:alias = [eE] [+\-]? decimal-digit+;
-float          = decimal-digit+ "." decimal-digit* exponent?
-               | "." decimal-digit+ exponent?
-               | decimal-digit+ exponent;
+exponent:alias:nows = [eE] [+\-]? decimal-digit+;
+float:nows          = decimal-digit+ "." decimal-digit* exponent?
+                    | "." decimal-digit+ exponent?
+                    | decimal-digit+ exponent;
 
-number:alias = "-"? (int | float);
+number:alias:nows = "-"? (int | float);
 
-string = "\"" ([^\\"] | "\\" .)* "\"";
-regexp = "/" ([^\\/] | "\\" .)* "/";
-symbol = [a-zA-Z_] [a-zA-z0-9_]*;
+string:nows = "\"" ([^\\"] | "\\" .)* "\"";
+regexp:nows = "/" ([^\\/] | "\\" .)* "/";
+symbol:nows = [a-zA-Z_] [a-zA-z0-9_]*;
 
 arg:alias  = number | string | regexp;
-args:alias = arg (wsc* "," wsc* arg)*;
-term:alias = symbol wsc* "(" wsc* args? wsc* ")";
+args:alias = arg ("," arg)*;
+term:alias = symbol "(" args? ")";
 
 predicate        = term;
-predicates:alias = "*" | predicate (wsc* "&&" wsc* predicate)*;
+predicates:alias = "*" | predicate ("&&" predicate)*;
 
 filter        = term;
-filters:alias = filter (wsc* "->" wsc* filter)*;
+filters:alias = filter ("->" filter)*;
 
 address:alias = string;
 shunt         = "<shunt>";
 loopback      = "<loopback>";
 backend:alias = address | shunt | loopback;
 
-expression = predicates (wsc* "->" wsc* filters)? wsc* "->" wsc* backend;
+expression = predicates ("->" filters)? "->" backend;
 
 id:alias   = symbol;
-definition = id wsc* ":" wsc* expression;
+definition = id ":" expression;
 
-free-sep:alias    = (wsc | ";");
-sep:alias         = wsc* ";" free-sep*;
-definitions:alias = free-sep* definition (sep definition)* free-sep*;
+definitions:alias = ";"* definition (";"+ definition)* ";"*;
diff --git a/sexpr_test.go b/sexpr_test.go
index d28e92d..d907c6a 100644
--- a/sexpr_test.go
+++ b/sexpr_test.go
@@ -67,5 +67,31 @@ func TestSExpr(t *testing.T) {
 			}},
 		}},
 		ignorePosition: true,
+	}, {
+		title: "comment and expression",
+		text: `; some comment
+		       (some expression)`,
+		ignorePosition: true,
+		nodes: []*Node{{
+			Name: "list",
+			Nodes: []*Node{{
+				Name: "symbol",
+			}, {
+				Name: "symbol",
+			}},
+		}},
+	}, {
+		title: "empty comment and expression",
+		text: `;
+		       (some expression)`,
+		ignorePosition: true,
+		nodes: []*Node{{
+			Name: "list",
+			Nodes: []*Node{{
+				Name: "symbol",
+			}, {
+				Name: "symbol",
+			}},
+		}},
 	}})
 }
diff --git a/whitespace.go b/whitespace.go
index 2683a37..ff00779 100644
--- a/whitespace.go
+++ b/whitespace.go
@@ -2,6 +2,7 @@ package treerack
 
 import (
 	"fmt"
+	"strconv"
 	"strings"
 )
 
@@ -59,6 +60,8 @@ func patchName(s ...string) string {
 	return strings.Join(s, ":")
 }
 
+// TODO: check what's more useful: update quantified char classes or not
+
 func applyWhitespaceToSeq(s *sequenceDefinition) []definition {
 	var (
 		defs  []definition
@@ -78,7 +81,7 @@ func applyWhitespaceToSeq(s *sequenceDefinition) []definition {
 
 		singleItem := SequenceItem{Name: item.Name, Min: 1, Max: 1}
 
-		restName := patchName(item.Name, s.nodeName(), "wsrest")
+		restName := patchName(item.Name, s.nodeName(), "wsrest", strconv.Itoa(i))
 		restDef := newSequence(restName, Alias, []SequenceItem{whitespace, singleItem})
 		defs = append(defs, restDef)
 
@@ -99,7 +102,7 @@ func applyWhitespaceToSeq(s *sequenceDefinition) []definition {
 			continue
 		}
 
-		optName := patchName(item.Name, s.nodeName(), "wsopt")
+		optName := patchName(item.Name, s.nodeName(), "wsopt", strconv.Itoa(i))
 		optDef := newSequence(optName, Alias, []SequenceItem{whitespace, singleItem, restItems})
 		defs = append(defs, optDef)
 		items = append(items, SequenceItem{Name: optName, Min: 0, Max: 1})