TextFormat.md


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# Text Format

The purpose of this text format is to support:
* View Source on a WebAssembly module, thus fitting into the Web (where every
  source can be viewed) in a natural way.
* Presentation in browser development tools when source maps aren't present
  (which is necessarily the case with [the Minimum Viable Product (MVP)](MVP.md)).
* Writing WebAssembly code directly for reasons including pedagogical,
  experimental, debugging, optimization, and testing of the spec itself.

The text format is equivalent and isomorphic to the [binary format](BinaryEncoding.md).

The text format will be standardized, but only for tooling purposes:
* Compilers will support this format for `.S` and inline assembly.
* Debuggers and profilers will present binary code using this textual format.
* Browsers will not parse the textual format on regular web content in order to
  implement WebAssembly semantics.

Given that the code representation is actually an
[Abstract Syntax Tree](AstSemantics.md), the syntax would contain nested
statements and expressions (instead of the linear list of instructions most
assembly languages have).

There is no requirement to use JavaScript syntax; this format is not intended to
be evaluated or translated directly into JavaScript.

The text format isn't uniquely representable. Multiple textual files can assemble
to the same binary file, for example whitespace isn't relevant and memory initialization
can be broken out into smaller pieces in the text format.

The text format is precise in that values that cannot be accurately represented in the
binary format are considered invalid text. Floating-point numbers are therefore
represented as hexadecimal floating-point as specified by the C99 standard, which
IEEE-754-2008 section 5.12.3 also specifies. The textual format may be improved to also
support more human-readable representations, but never at the cost of accurate representation.