Power BI M语言报token comma expected 密钥波浪号位置语法错误

问题表现 #

在Power BI中编写调用必应地图REST v1路线接口的M语言自定义函数时，运行抛出语法错误，原始完整代码如下：

(LatStart as text, LonStart as text, LatDest as text, LonDest as text)=>
let
Source = Xml.Tables(Web.Contents("https://dev.virtualearth.net/REST/v1/Routes/",
[
RelativePath="DistanceMatrix",
Query =[
origins="" & LatStart & "," & LonStart &"",
destinations="" & LatDest & "," & LonDest & "",
travelMode="driving",
distanceUnit="km",
timeUnit="minute",
o="xml",
key=gu9tL5NeUo6CsNKZWj00~o05Bp1GQ76ISmSrxiptgBQ~AoBvsa-SMlEHUcZuCl6tIVBRbDZDq0QDBuZBdpNfTUao5AzK3ua-pwaBl1AcwiPu
]
]
)),
#"Geänderter Typ" = Table.TransformColumnTypes(Quelle,{{"Copyright", type text}, {"BrandLogoUri", type text}, {"StatusCode", Int64.Type}, {"StatusDescription", type text}, {"AuthenticationResultCode", type text}, {"TraceId", type text}}),
ResourceSets = #"Geänderter Typ"{0}[ResourceSets],
ResourceSet = ResourceSets{0}[ResourceSet],
#"Geänderter Typ1" = Table.TransformColumnTypes(ResourceSet,{{"EstimatedTotal", Int64.Type}}),
Resources = #"Geänderter Typ1"{0}[Resources],
Resource = Resources{0}[Resource],
Results = Resource{0}[Results],
Distance = Results{0}[Distance],
#"Geänderter Typ2" = Table.TransformColumnTypes(Distance,{{"OriginIndex", Int64.Type}, {"DestinationIndex", Int64.Type}, {"TravelDistance", Int64.Type}, {"TravelDuration", Int64.Type}, {"TotalWalkDuration", Int64.Type}})
in
#"Geänderter Typ2"

Power BI返回错误提示：token comma expected（应为逗号标记），错误定位在key=对应取值的第一个~符号位置，报错片段如下：

key=gu9tL5NeUo6CsNKZWj00~o05Bp1GQ76ISmSrxiptgBQ~AoBvsa-SMlEHUcZuCl6tIVBRbDZDq0QDBuZBdpNfTUao5AzK3ua-pwaBl1AcwiPu

错误原因 #

• 核心语法错误：M语言中记录结构的文本类型值必须用双引号包裹，代码里key参数后的必应密钥是文本值，但未加双引号，解析器会将无引号内容识别为标识符或运算表达式，把值内的~判定为运算符，无法解析Query记录的结构，最终抛出缺少逗号的错误。
• 隐性运行错误：代码中#"Geänderter Typ"步骤引用了不存在的Quelle对象，这是德语版Power BI生成步骤时的默认源表名，和前序定义的Source步骤名不匹配，修复语法错误后会触发「名称Quelle不存在」的运行时报错。

修复方法 #

1. 给key=后的密钥字符串首尾加上双引号，明确标记为文本类型
2. 将#"Geänderter Typ"步骤中Table.TransformColumnTypes的第一个参数从Quelle修改为前序步骤名Source

修复后key参数的正确写法：

key="gu9tL5NeUo6CsNKZWj00~o05Bp1GQ76ISmSrxiptgBQ~AoBvsa-SMlEHUcZuCl6tIVBRbDZDq0QDBuZBdpNfTUao5AzK3ua-pwaBl1AcwiPu"

内容的提问来源于stack exchange，提问作者Sithys