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CommandLine

Command​

version​

version command prints the version of the next compiler. It prints the version of the next compiler and exits the program.

Example:

next version

Output:

next v0.0.4(main: 51864a35de7890d63bfd8acecdb62d20372ca963) built at 2024/09/27T22:58:21+0800 by go1.23.0

Flag​

-D​

-D represents the custom environment variables for code generation. The value is a map of environment variable names and their optional values.

Example:

next -D VERSION=2.1 -D DEBUG -D NAME=myapp ...
{{env.NAME}}
{{env.VERSION}}

Output:

myapp
2.1

-M​

-M represents the language-specific type mappings and features. %T%, %T.E%, %N%, %K%, %V% are placeholders replaced with actual types or values. %T.E% is the final element type of a vector or array. It's used to get the element type of multi-dimensional arrays.

Example:

next -M cpp.vector="std::vector<%T%>" \
     -M java.array="ArrayList<%T%>" \
     -M go.map="map[%K%]%V%" \
     -M python.ext=.py \
     -M protobuf.vector="repeated %T.E%" \
     -M ruby.comment="# %T%" \
     ...

-O​

-O represents the output directories for generated code of each target language.

Example:

next -O go=./output/go -O ts=./output/ts ...
tip

The {{meta.path}} is relative to the output directory.

-T​

-T represents the custom template directories or files for each target language. You can specify multiple templates for a single language.

Example:

next -T go=./templates/go \
     -T go=./templates/go_extra.npl \
     -T python=./templates/python.npl \
     ...

-X​

-X represents the custom annotation solver programs for code generation. Annotation solvers are executed in a separate process to solve annotations. All annotations are passed to the solver program via stdin and stdout. The built-in annotation next is reserved for the Next compiler.

Example:

next -X message="message-type-allocator message-types.json" ...
tip

In the example above, the message-type-allocator is a custom annotation solver program that reads the message types from the message-types.json file and rewrite the message types to the message-types.json file.

-header​

-header represents the header comment for generated code. The value is a string that represents the header comment for generated code. The default value is an empty string, which means default header comment is used.

Example:

next -header "Code generated by Next; DO NOT EDIT." ...
note

Do not add the comment characters like // or /* */ in the header. Next will add them automatically based on the target language comment style.

-test​

-test represents the test mode of the compiler. The default value is false, which means the compiler is not in test mode. The value true enables the test mode, which is used for validating but not generating code.

Example:

next -test ...

-v​

-v represents the verbosity level of the compiler. The default value is 0, which only shows error messages. The value 1 shows debug messages, and 2 shows trace messages. Usually, the trace message is used for debugging the compiler itself. Levels 1 (debug) and above enable execution of:

  • print and printf in Next source files (.next).
  • debug in Next template files (.npl).

Example:

next -v 1 ...
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