unify name-y things in grammar

This commit unifies the various types of named things in the PEG grammar
to a single pattern called ast.Name and gets rid of ast.String and
ast.QuotedString.  Now that the locators are all computed from the
underlying rule, we can easily have a single ast.Name that represents
different variations of names.  These changes will be used by a subequent PR
that will unify the get/file/pool operators into a single "from", which
is in turn needed by the upcoming SuperSQL additions.

compiler/ast/ast.go

@@ -131,20 +131,14 @@ type Glob struct {
 	Loc     `json:"loc"`
 }
 
-type QuotedString struct {
-	Kind string `json:"kind" unpack:""`
-	Text string `json:"text"`
-	Loc  `json:"loc"`
-}
-
 type Regexp struct {
 	Kind       string `json:"kind" unpack:""`
 	Pattern    string `json:"pattern"`
 	PatternPos int    `json:"pattern_pos"`
 	Loc        `json:"loc"`
 }
 
-type String struct {
+type Name struct {
 	Kind string `json:"kind" unpack:""`
 	Text string `json:"text"`
 	Loc  `json:"loc"`
@@ -155,10 +149,9 @@ type Pattern interface {
 	PatternAST()
 }
 
-func (*Glob) PatternAST()         {}
-func (*QuotedString) PatternAST() {}
-func (*Regexp) PatternAST()       {}
-func (*String) PatternAST()       {}
+func (*Glob) PatternAST()   {}
+func (*Regexp) PatternAST() {}
+func (*Name) PatternAST()   {}
 
 type RecordExpr struct {
 	Kind  string       `json:"kind" unpack:""`
@@ -173,7 +166,7 @@ type RecordElem interface {
 
 type FieldExpr struct {
 	Kind  string `json:"kind" unpack:""`
-	Name  string `json:"name"`
+	Name  *Name  `json:"name"`
 	Value Expr   `json:"value"`
 	Loc   `json:"loc"`
 }
@@ -397,10 +390,9 @@ type (
 		Loc   `json:"loc"`
 	}
 	Tail struct {
-		Kind       string `json:"kind" unpack:""`
-		KeywordPos int    `json:"keyword_pos"`
-		Count      Expr   `json:"count"`
-		Loc        `json:"loc"`
+		Kind  string `json:"kind" unpack:""`
+		Count Expr   `json:"count"`
+		Loc   `json:"loc"`
 	}
 	Pass struct {
 		Kind string `json:"kind" unpack:""`
@@ -412,9 +404,7 @@ type (
 		Loc   `json:"loc"`
 	}
 	Summarize struct {
-		Kind string `json:"kind" unpack:""`
-		// StartPos is not called KeywordPos for Summarize since the "summarize"
-		// keyword is optional.
+		Kind  string      `json:"kind" unpack:""`
 		Limit int         `json:"limit"`
 		Keys  Assignments `json:"keys"`
 		Aggs  Assignments `json:"aggs"`
@@ -509,17 +499,17 @@ type (
 	}
 	Load struct {
 		Kind    string `json:"kind" unpack:""`
-		Pool    string `json:"pool"` // ast.String etc
-		Branch  string `json:"branch"`
-		Author  string `json:"author"`
-		Message string `json:"message"`
-		Meta    string `json:"meta"`
+		Pool    *Name  `json:"pool"`
+		Branch  *Name  `json:"branch"`
+		Author  *Name  `json:"author"`
+		Message *Name  `json:"message"`
+		Meta    *Name  `json:"meta"`
 		Loc     `json:"loc"`
 	}
 	Assert struct {
 		Kind string `json:"kind" unpack:""`
 		Expr Expr   `json:"expr"`
-		Text string `json:"text"` //XXX text?
+		Text string `json:"text"`
 		Loc  `json:"loc"`
 	}
 	Output struct {
@@ -540,18 +530,18 @@ type (
 	File struct {
 		Kind     string     `json:"kind" unpack:""`
 		Path     Pattern    `json:"path"`
-		Format   string     `json:"format"`
+		Format   *Name      `json:"format"`
 		SortKeys []SortExpr `json:"sort_keys"`
 		Loc      `json:"loc"`
 	}
 	HTTP struct {
 		Kind     string      `json:"kind" unpack:""`
 		URL      Pattern     `json:"url"`
-		Format   string      `json:"format"`
+		Format   *Name       `json:"format"`
 		SortKeys []SortExpr  `json:"sort_keys"`
-		Method   string      `json:"method"`
+		Method   *Name       `json:"method"`
 		Headers  *RecordExpr `json:"headers"`
-		Body     string      `json:"body"`
+		Body     *Name       `json:"body"`
 		Loc      `json:"loc"`
 	}
 	Pool struct {
@@ -567,8 +557,8 @@ type (
 
 type PoolSpec struct {
 	Pool   Pattern `json:"pool"`
-	Commit string  `json:"commit"`
-	Meta   string  `json:"meta"`
+	Commit *Name   `json:"commit"`
+	Meta   *Name   `json:"meta"`
 	Tap    bool    `json:"tap"`
 	Loc    `json:"loc"`
 }

compiler/ast/unpack.go

@@ -56,7 +56,6 @@ var unpacker = unpack.New(
 	Pool{},
 	Primitive{},
 	Put{},
-	QuotedString{},
 	Record{},
 	Agg{},
 	Regexp{},
@@ -70,7 +69,7 @@ var unpacker = unpack.New(
 	Spread{},
 	SliceExpr{},
 	Sort{},
-	String{},
+	Name{},
 	OpDecl{},
 	Switch{},
 	Tail{},