feat(p/json): JSON path support

examples/gno.land/p/demo/json/buffer.gno

@@ -3,7 +3,6 @@ package json
 import (
 	"errors"
 	"io"
-	"strings"
 
 	"gno.land/p/demo/ufmt"
 )
@@ -28,6 +27,10 @@ func newBuffer(data []byte) *buffer {
 	}
 }
 
+func (b *buffer) reset() {
+	b.last = GO
+}
+
 // first retrieves the first non-whitespace (or other escaped) character in the buffer.
 func (b *buffer) first() (byte, error) {
 	for ; b.index < b.length; b.index++ {
@@ -122,16 +125,7 @@ func (b *buffer) skipAny(endTokens map[byte]bool) error {
 		b.index++
 	}
 
-	// build error message
-	var tokens []string
-	for token := range endTokens {
-		tokens = append(tokens, string(token))
-	}
-
-	return ufmt.Errorf(
-		"EOF reached before encountering one of the expected tokens: %s",
-		strings.Join(tokens, ", "),
-	)
+	return io.EOF
 }
 
 // skipAndReturnIndex moves the buffer index forward by one and returns the new index.
@@ -175,9 +169,9 @@ var significantTokens = map[byte]bool{
 
 // filterTokens stores the filter expression tokens.
 var filterTokens = map[byte]bool{
-	aesterisk: true, // wildcard
-	andSign:   true,
-	orSign:    true,
+	asterisk: true, // wildcard
+	andSign:  true,
+	orSign:   true,
 }
 
 // skipToNextSignificantToken advances the buffer index to the next significant character.
@@ -219,121 +213,6 @@ func (b *buffer) backslash() bool {
 	return count%2 != 0
 }
 
-// numIndex holds a map of valid numeric characters
-var numIndex = map[byte]bool{
-	'0': true,
-	'1': true,
-	'2': true,
-	'3': true,
-	'4': true,
-	'5': true,
-	'6': true,
-	'7': true,
-	'8': true,
-	'9': true,
-	'.': true,
-	'e': true,
-	'E': true,
-}
-
-// pathToken checks if the current token is a valid JSON path token.
-func (b *buffer) pathToken() error {
-	var stack []byte
-
-	inToken := false
-	inNumber := false
-	first := b.index
-
-	for b.index < b.length {
-		c := b.data[b.index]
-
-		switch {
-		case c == doubleQuote || c == singleQuote:
-			inToken = true
-			if err := b.step(); err != nil {
-				return errors.New("error stepping through buffer")
-			}
-
-			if err := b.skip(c); err != nil {
-				return errors.New("unmatched quote in path")
-			}
-
-			if b.index >= b.length {
-				return errors.New("unmatched quote in path")
-			}
-
-		case c == bracketOpen || c == parenOpen:
-			inToken = true
-			stack = append(stack, c)
-
-		case c == bracketClose || c == parenClose:
-			inToken = true
-			if len(stack) == 0 || (c == bracketClose && stack[len(stack)-1] != bracketOpen) || (c == parenClose && stack[len(stack)-1] != parenOpen) {
-				return errors.New("mismatched bracket or parenthesis")
-			}
-
-			stack = stack[:len(stack)-1]
-
-		case pathStateContainsValidPathToken(c):
-			inToken = true
-
-		case c == plus || c == minus:
-			if inNumber || (b.index > 0 && numIndex[b.data[b.index-1]]) {
-				inToken = true
-			} else if !inToken && (b.index+1 < b.length && numIndex[b.data[b.index+1]]) {
-				inToken = true
-				inNumber = true
-			} else if !inToken {
-				return errors.New("unexpected operator at start of token")
-			}
-
-		default:
-			if len(stack) != 0 || inToken {
-				inToken = true
-			} else {
-				goto end
-			}
-		}
-
-		b.index++
-	}
-
-end:
-	if len(stack) != 0 {
-		return errors.New("unclosed bracket or parenthesis at end of path")
-	}
-
-	if first == b.index {
-		return errors.New("no token found")
-	}
-
-	if inNumber && !numIndex[b.data[b.index-1]] {
-		inNumber = false
-	}
-
-	return nil
-}
-
-func pathStateContainsValidPathToken(c byte) bool {
-	if _, ok := significantTokens[c]; ok {
-		return true
-	}
-
-	if _, ok := filterTokens[c]; ok {
-		return true
-	}
-
-	if _, ok := numIndex[c]; ok {
-		return true
-	}
-
-	if 'A' <= c && c <= 'Z' || 'a' <= c && c <= 'z' {
-		return true
-	}
-
-	return false
-}
-
 func (b *buffer) numeric(token bool) error {
 	if token {
 		b.last = GO
@@ -483,3 +362,121 @@ func numberKind2f64(value interface{}) (result float64, err error) {
 
 	return
 }
+
+// numIndex holds a map of valid numeric characters
+var numIndex = map[byte]bool{
+	'0': true,
+	'1': true,
+	'2': true,
+	'3': true,
+	'4': true,
+	'5': true,
+	'6': true,
+	'7': true,
+	'8': true,
+	'9': true,
+	'.': true,
+	'e': true,
+	'E': true,
+}
+
+// pathToken checks if the current token is a valid JSON path token.
+func (b *buffer) pathToken() error {
+	var stack []byte
+
+	inToken := false
+	inNumber := false
+	first := b.index
+
+	for b.index < b.length {
+		c := b.data[b.index]
+
+		switch {
+		case c == singleQuote:
+			fallthrough
+
+		case c == doubleQuote:
+			inToken = true
+			if err := b.step(); err != nil {
+				return errors.New("error stepping through buffer")
+			}
+
+			if err := b.skip(c); err != nil {
+				return errors.New("unmatched quote in path")
+			}
+
+			if b.index >= b.length {
+				return errors.New("unmatched quote in path")
+			}
+
+		case c == bracketOpen || c == parenOpen:
+			inToken = true
+			stack = append(stack, c)
+
+		case c == bracketClose || c == parenClose:
+			inToken = true
+			if len(stack) == 0 || (c == bracketClose && stack[len(stack)-1] != bracketOpen) || (c == parenClose && stack[len(stack)-1] != parenOpen) {
+				return errors.New("mismatched bracket or parenthesis")
+			}
+
+			stack = stack[:len(stack)-1]
+
+		case pathStateContainsValidPathToken(c):
+			inToken = true
+
+		case c == plus || c == minus:
+			if inNumber || (b.index > 0 && numIndex[b.data[b.index-1]]) {
+				inToken = true
+			} else if !inToken && (b.index+1 < b.length && numIndex[b.data[b.index+1]]) {
+				inToken = true
+				inNumber = true
+			} else if !inToken {
+				return errors.New("unexpected operator at start of token")
+			}
+
+		default:
+			if len(stack) != 0 || inToken {
+				inToken = true
+			} else {
+				goto end
+			}
+		}
+
+		b.index++
+	}
+
+end:
+	if len(stack) != 0 {
+		return errors.New("unclosed bracket or parenthesis at end of path")
+	}
+
+	if first == b.index {
+		return errors.New("no token found")
+	}
+
+	if inNumber && !numIndex[b.data[b.index-1]] {
+		inNumber = false
+	}
+
+	return nil
+}
+
+func pathStateContainsValidPathToken(c byte) bool {
+	if _, ok := significantTokens[c]; ok {
+		return true
+	}
+
+	if _, ok := filterTokens[c]; ok {
+		return true
+	}
+
+	if _, ok := numIndex[c]; ok {
+		return true
+	}
+
+	if 'A' <= c && c <= 'Z' || 'a' <= c && c <= 'z' {
+		return true
+	}
+
+	return false
+}

examples/gno.land/p/demo/json/buffer_test.gno

@@ -1,6 +1,9 @@
 package json
 
-import "testing"
+import (
+	"io"
+	"testing"
+)
 
 func TestBufferCurrent(t *testing.T) {
 	tests := []struct {