843 lines
		
	
	
		
			18 KiB
		
	
	
	
		
			Go
		
	
	
	
			
		
		
	
	
			843 lines
		
	
	
		
			18 KiB
		
	
	
	
		
			Go
		
	
	
	
package jmespath
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import (
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	"encoding/json"
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	"errors"
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	"fmt"
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	"math"
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	"reflect"
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	"sort"
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	"strconv"
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	"strings"
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	"unicode/utf8"
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)
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type jpFunction func(arguments []interface{}) (interface{}, error)
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type jpType string
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const (
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	jpUnknown     jpType = "unknown"
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	jpNumber      jpType = "number"
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	jpString      jpType = "string"
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	jpArray       jpType = "array"
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	jpObject      jpType = "object"
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	jpArrayNumber jpType = "array[number]"
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	jpArrayString jpType = "array[string]"
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	jpExpref      jpType = "expref"
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	jpAny         jpType = "any"
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)
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type functionEntry struct {
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	name      string
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	arguments []argSpec
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	handler   jpFunction
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	hasExpRef bool
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}
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type argSpec struct {
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	types    []jpType
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	variadic bool
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}
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type byExprString struct {
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	intr     *treeInterpreter
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	node     ASTNode
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	items    []interface{}
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	hasError bool
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}
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func (a *byExprString) Len() int {
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	return len(a.items)
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}
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func (a *byExprString) Swap(i, j int) {
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	a.items[i], a.items[j] = a.items[j], a.items[i]
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}
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func (a *byExprString) Less(i, j int) bool {
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	first, err := a.intr.Execute(a.node, a.items[i])
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	if err != nil {
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		a.hasError = true
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		// Return a dummy value.
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		return true
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	}
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	ith, ok := first.(string)
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	if !ok {
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		a.hasError = true
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		return true
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	}
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	second, err := a.intr.Execute(a.node, a.items[j])
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	if err != nil {
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		a.hasError = true
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		// Return a dummy value.
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		return true
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	}
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	jth, ok := second.(string)
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	if !ok {
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		a.hasError = true
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		return true
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	}
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	return ith < jth
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}
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type byExprFloat struct {
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	intr     *treeInterpreter
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	node     ASTNode
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	items    []interface{}
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	hasError bool
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}
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func (a *byExprFloat) Len() int {
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	return len(a.items)
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}
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func (a *byExprFloat) Swap(i, j int) {
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	a.items[i], a.items[j] = a.items[j], a.items[i]
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}
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func (a *byExprFloat) Less(i, j int) bool {
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	first, err := a.intr.Execute(a.node, a.items[i])
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	if err != nil {
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		a.hasError = true
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		// Return a dummy value.
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		return true
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	}
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	ith, ok := first.(float64)
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	if !ok {
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		a.hasError = true
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		return true
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	}
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	second, err := a.intr.Execute(a.node, a.items[j])
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	if err != nil {
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		a.hasError = true
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		// Return a dummy value.
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		return true
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	}
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	jth, ok := second.(float64)
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	if !ok {
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		a.hasError = true
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		return true
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	}
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	return ith < jth
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}
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type functionCaller struct {
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	functionTable map[string]functionEntry
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}
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func newFunctionCaller() *functionCaller {
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	caller := &functionCaller{}
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	caller.functionTable = map[string]functionEntry{
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		"length": {
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			name: "length",
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			arguments: []argSpec{
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				{types: []jpType{jpString, jpArray, jpObject}},
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			},
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			handler: jpfLength,
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		},
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		"starts_with": {
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			name: "starts_with",
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			arguments: []argSpec{
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				{types: []jpType{jpString}},
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				{types: []jpType{jpString}},
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			},
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			handler: jpfStartsWith,
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		},
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		"abs": {
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			name: "abs",
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			arguments: []argSpec{
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				{types: []jpType{jpNumber}},
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			},
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			handler: jpfAbs,
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		},
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		"avg": {
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			name: "avg",
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			arguments: []argSpec{
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				{types: []jpType{jpArrayNumber}},
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			},
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			handler: jpfAvg,
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		},
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		"ceil": {
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			name: "ceil",
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			arguments: []argSpec{
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				{types: []jpType{jpNumber}},
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			},
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			handler: jpfCeil,
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		},
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		"contains": {
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			name: "contains",
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			arguments: []argSpec{
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				{types: []jpType{jpArray, jpString}},
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				{types: []jpType{jpAny}},
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			},
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			handler: jpfContains,
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		},
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		"ends_with": {
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			name: "ends_with",
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			arguments: []argSpec{
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				{types: []jpType{jpString}},
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				{types: []jpType{jpString}},
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			},
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			handler: jpfEndsWith,
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		},
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		"floor": {
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			name: "floor",
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			arguments: []argSpec{
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				{types: []jpType{jpNumber}},
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			},
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			handler: jpfFloor,
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		},
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		"map": {
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			name: "amp",
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			arguments: []argSpec{
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				{types: []jpType{jpExpref}},
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				{types: []jpType{jpArray}},
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			},
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			handler:   jpfMap,
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			hasExpRef: true,
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		},
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		"max": {
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			name: "max",
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			arguments: []argSpec{
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				{types: []jpType{jpArrayNumber, jpArrayString}},
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			},
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			handler: jpfMax,
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		},
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		"merge": {
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			name: "merge",
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			arguments: []argSpec{
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				{types: []jpType{jpObject}, variadic: true},
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			},
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			handler: jpfMerge,
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		},
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		"max_by": {
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			name: "max_by",
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			arguments: []argSpec{
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				{types: []jpType{jpArray}},
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				{types: []jpType{jpExpref}},
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			},
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			handler:   jpfMaxBy,
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			hasExpRef: true,
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		},
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		"sum": {
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			name: "sum",
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			arguments: []argSpec{
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				{types: []jpType{jpArrayNumber}},
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			},
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			handler: jpfSum,
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		},
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		"min": {
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			name: "min",
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			arguments: []argSpec{
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				{types: []jpType{jpArrayNumber, jpArrayString}},
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			},
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			handler: jpfMin,
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		},
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		"min_by": {
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			name: "min_by",
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			arguments: []argSpec{
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				{types: []jpType{jpArray}},
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				{types: []jpType{jpExpref}},
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			},
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			handler:   jpfMinBy,
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			hasExpRef: true,
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		},
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		"type": {
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			name: "type",
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			arguments: []argSpec{
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				{types: []jpType{jpAny}},
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			},
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			handler: jpfType,
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		},
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		"keys": {
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			name: "keys",
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			arguments: []argSpec{
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				{types: []jpType{jpObject}},
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			},
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			handler: jpfKeys,
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		},
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		"values": {
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			name: "values",
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			arguments: []argSpec{
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				{types: []jpType{jpObject}},
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			},
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			handler: jpfValues,
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		},
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		"sort": {
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			name: "sort",
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			arguments: []argSpec{
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				{types: []jpType{jpArrayString, jpArrayNumber}},
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			},
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			handler: jpfSort,
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		},
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		"sort_by": {
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			name: "sort_by",
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			arguments: []argSpec{
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				{types: []jpType{jpArray}},
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				{types: []jpType{jpExpref}},
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			},
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			handler:   jpfSortBy,
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			hasExpRef: true,
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		},
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		"join": {
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			name: "join",
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			arguments: []argSpec{
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				{types: []jpType{jpString}},
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				{types: []jpType{jpArrayString}},
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			},
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			handler: jpfJoin,
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		},
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		"reverse": {
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			name: "reverse",
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			arguments: []argSpec{
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				{types: []jpType{jpArray, jpString}},
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			},
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			handler: jpfReverse,
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		},
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		"to_array": {
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			name: "to_array",
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			arguments: []argSpec{
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				{types: []jpType{jpAny}},
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			},
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			handler: jpfToArray,
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		},
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		"to_string": {
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			name: "to_string",
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			arguments: []argSpec{
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				{types: []jpType{jpAny}},
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			},
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			handler: jpfToString,
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		},
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		"to_number": {
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			name: "to_number",
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			arguments: []argSpec{
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				{types: []jpType{jpAny}},
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			},
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			handler: jpfToNumber,
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		},
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		"not_null": {
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			name: "not_null",
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			arguments: []argSpec{
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				{types: []jpType{jpAny}, variadic: true},
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			},
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			handler: jpfNotNull,
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		},
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	}
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	return caller
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}
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func (e *functionEntry) resolveArgs(arguments []interface{}) ([]interface{}, error) {
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	if len(e.arguments) == 0 {
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		return arguments, nil
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	}
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	if !e.arguments[len(e.arguments)-1].variadic {
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		if len(e.arguments) != len(arguments) {
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			return nil, errors.New("incorrect number of args")
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		}
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		for i, spec := range e.arguments {
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			userArg := arguments[i]
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			err := spec.typeCheck(userArg)
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			if err != nil {
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				return nil, err
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			}
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		}
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		return arguments, nil
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	}
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	if len(arguments) < len(e.arguments) {
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		return nil, errors.New("Invalid arity.")
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	}
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	return arguments, nil
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}
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func (a *argSpec) typeCheck(arg interface{}) error {
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	for _, t := range a.types {
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		switch t {
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		case jpNumber:
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			if _, ok := arg.(float64); ok {
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				return nil
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			}
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		case jpString:
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			if _, ok := arg.(string); ok {
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				return nil
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			}
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		case jpArray:
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			if isSliceType(arg) {
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				return nil
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			}
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		case jpObject:
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			if _, ok := arg.(map[string]interface{}); ok {
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				return nil
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			}
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		case jpArrayNumber:
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			if _, ok := toArrayNum(arg); ok {
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				return nil
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			}
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		case jpArrayString:
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			if _, ok := toArrayStr(arg); ok {
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				return nil
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			}
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		case jpAny:
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			return nil
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		case jpExpref:
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			if _, ok := arg.(expRef); ok {
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				return nil
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			}
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		}
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	}
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	return fmt.Errorf("Invalid type for: %v, expected: %#v", arg, a.types)
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}
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func (f *functionCaller) CallFunction(name string, arguments []interface{}, intr *treeInterpreter) (interface{}, error) {
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	entry, ok := f.functionTable[name]
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	if !ok {
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		return nil, errors.New("unknown function: " + name)
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	}
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	resolvedArgs, err := entry.resolveArgs(arguments)
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	if err != nil {
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		return nil, err
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	}
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	if entry.hasExpRef {
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		var extra []interface{}
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		extra = append(extra, intr)
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		resolvedArgs = append(extra, resolvedArgs...)
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	}
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	return entry.handler(resolvedArgs)
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}
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func jpfAbs(arguments []interface{}) (interface{}, error) {
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	num := arguments[0].(float64)
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	return math.Abs(num), nil
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}
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func jpfLength(arguments []interface{}) (interface{}, error) {
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	arg := arguments[0]
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	if c, ok := arg.(string); ok {
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		return float64(utf8.RuneCountInString(c)), nil
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	} else if isSliceType(arg) {
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		v := reflect.ValueOf(arg)
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		return float64(v.Len()), nil
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	} else if c, ok := arg.(map[string]interface{}); ok {
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		return float64(len(c)), nil
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	}
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	return nil, errors.New("could not compute length()")
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}
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func jpfStartsWith(arguments []interface{}) (interface{}, error) {
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	search := arguments[0].(string)
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	prefix := arguments[1].(string)
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	return strings.HasPrefix(search, prefix), nil
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}
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func jpfAvg(arguments []interface{}) (interface{}, error) {
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	// We've already type checked the value so we can safely use
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	// type assertions.
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	args := arguments[0].([]interface{})
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						|
	length := float64(len(args))
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						|
	numerator := 0.0
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						|
	for _, n := range args {
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		numerator += n.(float64)
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	}
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	return numerator / length, nil
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}
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func jpfCeil(arguments []interface{}) (interface{}, error) {
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	val := arguments[0].(float64)
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	return math.Ceil(val), nil
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}
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func jpfContains(arguments []interface{}) (interface{}, error) {
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	search := arguments[0]
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	el := arguments[1]
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	if searchStr, ok := search.(string); ok {
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		if elStr, ok := el.(string); ok {
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			return strings.Index(searchStr, elStr) != -1, nil
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		}
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		return false, nil
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	}
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	// Otherwise this is a generic contains for []interface{}
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	general := search.([]interface{})
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						|
	for _, item := range general {
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						|
		if item == el {
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			return true, nil
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		}
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	}
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	return false, nil
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}
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func jpfEndsWith(arguments []interface{}) (interface{}, error) {
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	search := arguments[0].(string)
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						|
	suffix := arguments[1].(string)
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	return strings.HasSuffix(search, suffix), nil
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}
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func jpfFloor(arguments []interface{}) (interface{}, error) {
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	val := arguments[0].(float64)
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	return math.Floor(val), nil
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}
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func jpfMap(arguments []interface{}) (interface{}, error) {
 | 
						|
	intr := arguments[0].(*treeInterpreter)
 | 
						|
	exp := arguments[1].(expRef)
 | 
						|
	node := exp.ref
 | 
						|
	arr := arguments[2].([]interface{})
 | 
						|
	mapped := make([]interface{}, 0, len(arr))
 | 
						|
	for _, value := range arr {
 | 
						|
		current, err := intr.Execute(node, value)
 | 
						|
		if err != nil {
 | 
						|
			return nil, err
 | 
						|
		}
 | 
						|
		mapped = append(mapped, current)
 | 
						|
	}
 | 
						|
	return mapped, nil
 | 
						|
}
 | 
						|
func jpfMax(arguments []interface{}) (interface{}, error) {
 | 
						|
	if items, ok := toArrayNum(arguments[0]); ok {
 | 
						|
		if len(items) == 0 {
 | 
						|
			return nil, nil
 | 
						|
		}
 | 
						|
		if len(items) == 1 {
 | 
						|
			return items[0], nil
 | 
						|
		}
 | 
						|
		best := items[0]
 | 
						|
		for _, item := range items[1:] {
 | 
						|
			if item > best {
 | 
						|
				best = item
 | 
						|
			}
 | 
						|
		}
 | 
						|
		return best, nil
 | 
						|
	}
 | 
						|
	// Otherwise we're dealing with a max() of strings.
 | 
						|
	items, _ := toArrayStr(arguments[0])
 | 
						|
	if len(items) == 0 {
 | 
						|
		return nil, nil
 | 
						|
	}
 | 
						|
	if len(items) == 1 {
 | 
						|
		return items[0], nil
 | 
						|
	}
 | 
						|
	best := items[0]
 | 
						|
	for _, item := range items[1:] {
 | 
						|
		if item > best {
 | 
						|
			best = item
 | 
						|
		}
 | 
						|
	}
 | 
						|
	return best, nil
 | 
						|
}
 | 
						|
func jpfMerge(arguments []interface{}) (interface{}, error) {
 | 
						|
	final := make(map[string]interface{})
 | 
						|
	for _, m := range arguments {
 | 
						|
		mapped := m.(map[string]interface{})
 | 
						|
		for key, value := range mapped {
 | 
						|
			final[key] = value
 | 
						|
		}
 | 
						|
	}
 | 
						|
	return final, nil
 | 
						|
}
 | 
						|
func jpfMaxBy(arguments []interface{}) (interface{}, error) {
 | 
						|
	intr := arguments[0].(*treeInterpreter)
 | 
						|
	arr := arguments[1].([]interface{})
 | 
						|
	exp := arguments[2].(expRef)
 | 
						|
	node := exp.ref
 | 
						|
	if len(arr) == 0 {
 | 
						|
		return nil, nil
 | 
						|
	} else if len(arr) == 1 {
 | 
						|
		return arr[0], nil
 | 
						|
	}
 | 
						|
	start, err := intr.Execute(node, arr[0])
 | 
						|
	if err != nil {
 | 
						|
		return nil, err
 | 
						|
	}
 | 
						|
	switch t := start.(type) {
 | 
						|
	case float64:
 | 
						|
		bestVal := t
 | 
						|
		bestItem := arr[0]
 | 
						|
		for _, item := range arr[1:] {
 | 
						|
			result, err := intr.Execute(node, item)
 | 
						|
			if err != nil {
 | 
						|
				return nil, err
 | 
						|
			}
 | 
						|
			current, ok := result.(float64)
 | 
						|
			if !ok {
 | 
						|
				return nil, errors.New("invalid type, must be number")
 | 
						|
			}
 | 
						|
			if current > bestVal {
 | 
						|
				bestVal = current
 | 
						|
				bestItem = item
 | 
						|
			}
 | 
						|
		}
 | 
						|
		return bestItem, nil
 | 
						|
	case string:
 | 
						|
		bestVal := t
 | 
						|
		bestItem := arr[0]
 | 
						|
		for _, item := range arr[1:] {
 | 
						|
			result, err := intr.Execute(node, item)
 | 
						|
			if err != nil {
 | 
						|
				return nil, err
 | 
						|
			}
 | 
						|
			current, ok := result.(string)
 | 
						|
			if !ok {
 | 
						|
				return nil, errors.New("invalid type, must be string")
 | 
						|
			}
 | 
						|
			if current > bestVal {
 | 
						|
				bestVal = current
 | 
						|
				bestItem = item
 | 
						|
			}
 | 
						|
		}
 | 
						|
		return bestItem, nil
 | 
						|
	default:
 | 
						|
		return nil, errors.New("invalid type, must be number of string")
 | 
						|
	}
 | 
						|
}
 | 
						|
func jpfSum(arguments []interface{}) (interface{}, error) {
 | 
						|
	items, _ := toArrayNum(arguments[0])
 | 
						|
	sum := 0.0
 | 
						|
	for _, item := range items {
 | 
						|
		sum += item
 | 
						|
	}
 | 
						|
	return sum, nil
 | 
						|
}
 | 
						|
 | 
						|
func jpfMin(arguments []interface{}) (interface{}, error) {
 | 
						|
	if items, ok := toArrayNum(arguments[0]); ok {
 | 
						|
		if len(items) == 0 {
 | 
						|
			return nil, nil
 | 
						|
		}
 | 
						|
		if len(items) == 1 {
 | 
						|
			return items[0], nil
 | 
						|
		}
 | 
						|
		best := items[0]
 | 
						|
		for _, item := range items[1:] {
 | 
						|
			if item < best {
 | 
						|
				best = item
 | 
						|
			}
 | 
						|
		}
 | 
						|
		return best, nil
 | 
						|
	}
 | 
						|
	items, _ := toArrayStr(arguments[0])
 | 
						|
	if len(items) == 0 {
 | 
						|
		return nil, nil
 | 
						|
	}
 | 
						|
	if len(items) == 1 {
 | 
						|
		return items[0], nil
 | 
						|
	}
 | 
						|
	best := items[0]
 | 
						|
	for _, item := range items[1:] {
 | 
						|
		if item < best {
 | 
						|
			best = item
 | 
						|
		}
 | 
						|
	}
 | 
						|
	return best, nil
 | 
						|
}
 | 
						|
 | 
						|
func jpfMinBy(arguments []interface{}) (interface{}, error) {
 | 
						|
	intr := arguments[0].(*treeInterpreter)
 | 
						|
	arr := arguments[1].([]interface{})
 | 
						|
	exp := arguments[2].(expRef)
 | 
						|
	node := exp.ref
 | 
						|
	if len(arr) == 0 {
 | 
						|
		return nil, nil
 | 
						|
	} else if len(arr) == 1 {
 | 
						|
		return arr[0], nil
 | 
						|
	}
 | 
						|
	start, err := intr.Execute(node, arr[0])
 | 
						|
	if err != nil {
 | 
						|
		return nil, err
 | 
						|
	}
 | 
						|
	if t, ok := start.(float64); ok {
 | 
						|
		bestVal := t
 | 
						|
		bestItem := arr[0]
 | 
						|
		for _, item := range arr[1:] {
 | 
						|
			result, err := intr.Execute(node, item)
 | 
						|
			if err != nil {
 | 
						|
				return nil, err
 | 
						|
			}
 | 
						|
			current, ok := result.(float64)
 | 
						|
			if !ok {
 | 
						|
				return nil, errors.New("invalid type, must be number")
 | 
						|
			}
 | 
						|
			if current < bestVal {
 | 
						|
				bestVal = current
 | 
						|
				bestItem = item
 | 
						|
			}
 | 
						|
		}
 | 
						|
		return bestItem, nil
 | 
						|
	} else if t, ok := start.(string); ok {
 | 
						|
		bestVal := t
 | 
						|
		bestItem := arr[0]
 | 
						|
		for _, item := range arr[1:] {
 | 
						|
			result, err := intr.Execute(node, item)
 | 
						|
			if err != nil {
 | 
						|
				return nil, err
 | 
						|
			}
 | 
						|
			current, ok := result.(string)
 | 
						|
			if !ok {
 | 
						|
				return nil, errors.New("invalid type, must be string")
 | 
						|
			}
 | 
						|
			if current < bestVal {
 | 
						|
				bestVal = current
 | 
						|
				bestItem = item
 | 
						|
			}
 | 
						|
		}
 | 
						|
		return bestItem, nil
 | 
						|
	} else {
 | 
						|
		return nil, errors.New("invalid type, must be number of string")
 | 
						|
	}
 | 
						|
}
 | 
						|
func jpfType(arguments []interface{}) (interface{}, error) {
 | 
						|
	arg := arguments[0]
 | 
						|
	if _, ok := arg.(float64); ok {
 | 
						|
		return "number", nil
 | 
						|
	}
 | 
						|
	if _, ok := arg.(string); ok {
 | 
						|
		return "string", nil
 | 
						|
	}
 | 
						|
	if _, ok := arg.([]interface{}); ok {
 | 
						|
		return "array", nil
 | 
						|
	}
 | 
						|
	if _, ok := arg.(map[string]interface{}); ok {
 | 
						|
		return "object", nil
 | 
						|
	}
 | 
						|
	if arg == nil {
 | 
						|
		return "null", nil
 | 
						|
	}
 | 
						|
	if arg == true || arg == false {
 | 
						|
		return "boolean", nil
 | 
						|
	}
 | 
						|
	return nil, errors.New("unknown type")
 | 
						|
}
 | 
						|
func jpfKeys(arguments []interface{}) (interface{}, error) {
 | 
						|
	arg := arguments[0].(map[string]interface{})
 | 
						|
	collected := make([]interface{}, 0, len(arg))
 | 
						|
	for key := range arg {
 | 
						|
		collected = append(collected, key)
 | 
						|
	}
 | 
						|
	return collected, nil
 | 
						|
}
 | 
						|
func jpfValues(arguments []interface{}) (interface{}, error) {
 | 
						|
	arg := arguments[0].(map[string]interface{})
 | 
						|
	collected := make([]interface{}, 0, len(arg))
 | 
						|
	for _, value := range arg {
 | 
						|
		collected = append(collected, value)
 | 
						|
	}
 | 
						|
	return collected, nil
 | 
						|
}
 | 
						|
func jpfSort(arguments []interface{}) (interface{}, error) {
 | 
						|
	if items, ok := toArrayNum(arguments[0]); ok {
 | 
						|
		d := sort.Float64Slice(items)
 | 
						|
		sort.Stable(d)
 | 
						|
		final := make([]interface{}, len(d))
 | 
						|
		for i, val := range d {
 | 
						|
			final[i] = val
 | 
						|
		}
 | 
						|
		return final, nil
 | 
						|
	}
 | 
						|
	// Otherwise we're dealing with sort()'ing strings.
 | 
						|
	items, _ := toArrayStr(arguments[0])
 | 
						|
	d := sort.StringSlice(items)
 | 
						|
	sort.Stable(d)
 | 
						|
	final := make([]interface{}, len(d))
 | 
						|
	for i, val := range d {
 | 
						|
		final[i] = val
 | 
						|
	}
 | 
						|
	return final, nil
 | 
						|
}
 | 
						|
func jpfSortBy(arguments []interface{}) (interface{}, error) {
 | 
						|
	intr := arguments[0].(*treeInterpreter)
 | 
						|
	arr := arguments[1].([]interface{})
 | 
						|
	exp := arguments[2].(expRef)
 | 
						|
	node := exp.ref
 | 
						|
	if len(arr) == 0 {
 | 
						|
		return arr, nil
 | 
						|
	} else if len(arr) == 1 {
 | 
						|
		return arr, nil
 | 
						|
	}
 | 
						|
	start, err := intr.Execute(node, arr[0])
 | 
						|
	if err != nil {
 | 
						|
		return nil, err
 | 
						|
	}
 | 
						|
	if _, ok := start.(float64); ok {
 | 
						|
		sortable := &byExprFloat{intr, node, arr, false}
 | 
						|
		sort.Stable(sortable)
 | 
						|
		if sortable.hasError {
 | 
						|
			return nil, errors.New("error in sort_by comparison")
 | 
						|
		}
 | 
						|
		return arr, nil
 | 
						|
	} else if _, ok := start.(string); ok {
 | 
						|
		sortable := &byExprString{intr, node, arr, false}
 | 
						|
		sort.Stable(sortable)
 | 
						|
		if sortable.hasError {
 | 
						|
			return nil, errors.New("error in sort_by comparison")
 | 
						|
		}
 | 
						|
		return arr, nil
 | 
						|
	} else {
 | 
						|
		return nil, errors.New("invalid type, must be number of string")
 | 
						|
	}
 | 
						|
}
 | 
						|
func jpfJoin(arguments []interface{}) (interface{}, error) {
 | 
						|
	sep := arguments[0].(string)
 | 
						|
	// We can't just do arguments[1].([]string), we have to
 | 
						|
	// manually convert each item to a string.
 | 
						|
	arrayStr := []string{}
 | 
						|
	for _, item := range arguments[1].([]interface{}) {
 | 
						|
		arrayStr = append(arrayStr, item.(string))
 | 
						|
	}
 | 
						|
	return strings.Join(arrayStr, sep), nil
 | 
						|
}
 | 
						|
func jpfReverse(arguments []interface{}) (interface{}, error) {
 | 
						|
	if s, ok := arguments[0].(string); ok {
 | 
						|
		r := []rune(s)
 | 
						|
		for i, j := 0, len(r)-1; i < len(r)/2; i, j = i+1, j-1 {
 | 
						|
			r[i], r[j] = r[j], r[i]
 | 
						|
		}
 | 
						|
		return string(r), nil
 | 
						|
	}
 | 
						|
	items := arguments[0].([]interface{})
 | 
						|
	length := len(items)
 | 
						|
	reversed := make([]interface{}, length)
 | 
						|
	for i, item := range items {
 | 
						|
		reversed[length-(i+1)] = item
 | 
						|
	}
 | 
						|
	return reversed, nil
 | 
						|
}
 | 
						|
func jpfToArray(arguments []interface{}) (interface{}, error) {
 | 
						|
	if _, ok := arguments[0].([]interface{}); ok {
 | 
						|
		return arguments[0], nil
 | 
						|
	}
 | 
						|
	return arguments[:1:1], nil
 | 
						|
}
 | 
						|
func jpfToString(arguments []interface{}) (interface{}, error) {
 | 
						|
	if v, ok := arguments[0].(string); ok {
 | 
						|
		return v, nil
 | 
						|
	}
 | 
						|
	result, err := json.Marshal(arguments[0])
 | 
						|
	if err != nil {
 | 
						|
		return nil, err
 | 
						|
	}
 | 
						|
	return string(result), nil
 | 
						|
}
 | 
						|
func jpfToNumber(arguments []interface{}) (interface{}, error) {
 | 
						|
	arg := arguments[0]
 | 
						|
	if v, ok := arg.(float64); ok {
 | 
						|
		return v, nil
 | 
						|
	}
 | 
						|
	if v, ok := arg.(string); ok {
 | 
						|
		conv, err := strconv.ParseFloat(v, 64)
 | 
						|
		if err != nil {
 | 
						|
			return nil, nil
 | 
						|
		}
 | 
						|
		return conv, nil
 | 
						|
	}
 | 
						|
	if _, ok := arg.([]interface{}); ok {
 | 
						|
		return nil, nil
 | 
						|
	}
 | 
						|
	if _, ok := arg.(map[string]interface{}); ok {
 | 
						|
		return nil, nil
 | 
						|
	}
 | 
						|
	if arg == nil {
 | 
						|
		return nil, nil
 | 
						|
	}
 | 
						|
	if arg == true || arg == false {
 | 
						|
		return nil, nil
 | 
						|
	}
 | 
						|
	return nil, errors.New("unknown type")
 | 
						|
}
 | 
						|
func jpfNotNull(arguments []interface{}) (interface{}, error) {
 | 
						|
	for _, arg := range arguments {
 | 
						|
		if arg != nil {
 | 
						|
			return arg, nil
 | 
						|
		}
 | 
						|
	}
 | 
						|
	return nil, nil
 | 
						|
}
 |