Add noexponent struct tag for field-level float formatting #432
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Implements field level control of float formatting via json:"field,noexponent" struct tag to suppress exponential notation using format 'f' instead of 'g'. This allows mixing scientific and non-scientific notation in the same struct, providing more flexibility than global CLI flags. Implementation: - Add noExponent bool to fieldTags struct (gen/encoder.go) - Parse noexponent tag in parseFieldTags - Add Float32NoExp, Float64NoExp, Float32StrNoExp, Float64StrNoExp methods to jwriter.Writer - Add primitiveNoExpEncoders and primitiveStringNoExpEncoders encoder maps - Update genTypeEncoderNoCheck to check tag combinations and use appropriate encoder - Add test cases demonstrating the feature Generated code calls appropriate Writer methods: - Default: out.Float64() uses 'g' format - With noexponent: out.Float64NoExp() uses 'f' format - With string,noexponent: out.Float64StrNoExp() uses quoted 'f' format Follows existing pattern of asString tag → Float64Str() method. Related to issue mailru#425
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Summary
This PR implements field-level control of float formatting via the
json:"field,noexponent"struct tag, as discussed in #425.Instead of relying on global CLI flags, this allows developers to suppress exponential notation on a per-field basis using the
'f'format instead of the default'g'format.Implementation
Follows the existing pattern where different struct tags select different Writer methods (e.g.,
asString→Float64Str()).Changes:
noExponent booltofieldTagsstruct ingen/encoder.gonoexponenttag inparseFieldTags()jwriter/writer.go:Float32NoExp(),Float64NoExp()Float32StrNoExp(),Float64StrNoExp()primitiveNoExpEncodersandprimitiveStringNoExpEncodersgenTypeEncoderNoCheck()to check tag combinations and select appropriate encoderUsage Example
```go
type PriceData struct {
Scientific float64 `json:"sci"` // 1e8 (default 'g' format)
NoExp float64 `json:"price,noexponent"` // 100000000 ('f' format)
QuotedNoExp float64 `json:"str,string,noexponent"` // "100000000" (quoted + 'f')
}
```
Generated Code
The generator produces appropriate Writer method calls:
out.Float64(value)uses'g'formatnoexponent:out.Float64NoExp(value)uses'f'formatstring,noexponent:out.Float64StrNoExp(value)uses quoted'f'formatBenefits
omitempty,stringasString→Float64Str()patternCloses #425