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70 lines
1.9 KiB
Nim
70 lines
1.9 KiB
Nim
## Literal rendering for `{.ffiConst.}` values, shared by the C/C++/Rust generators.
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## The registry stores Nim's `$value`; each backend re-quotes it for its syntax.
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import std/strutils
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import ./types_ir
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func cByteEscape(ch: char): string =
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## 3-digit octal: C caps an octal escape at 3 digits, so a following digit
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## can't be swallowed into it the way it can with `\x`.
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return "\\" & toOct(ord(ch), 3)
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func rustByteEscape(ch: char): string =
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return "\\x" & toHex(ord(ch), 2)
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func escapeLit(
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s: string, byteEscape: proc(ch: char): string {.noSideEffect, nimcall.}
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): string =
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var escaped = ""
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for ch in s:
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case ch
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of '"':
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escaped.add("\\\"")
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of '\\':
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escaped.add("\\\\")
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of '\n':
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escaped.add("\\n")
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of '\r':
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escaped.add("\\r")
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of '\t':
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escaped.add("\\t")
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else:
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if ch < ' ' or ch == '\x7F':
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escaped.add(byteEscape(ch))
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else:
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escaped.add(ch)
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return escaped
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func cEscapeStringLit*(s: string): string =
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return escapeLit(s, cByteEscape)
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func rustEscapeStringLit*(s: string): string =
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return escapeLit(s, rustByteEscape)
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func cConstValue*(t: FFIType, value: string): string =
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## C/C++ literal. Every emission site is a typed declaration, so the declared
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## type already fixes the width; only the two cases the type can't rescue get
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## a suffix — `ULL` because a decimal above `INT64_MAX` fits no signed type,
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## and `f` because a bare `1.5` is a double and narrowing it warns.
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case t.kind
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of ftStr:
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return "\"" & cEscapeStringLit(value) & "\""
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of ftScalar:
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case t.scalar
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of skU64:
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return value & "ULL"
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of skF32:
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return value & "f"
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else:
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return value
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else:
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return value
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func rustConstValue*(t: FFIType, value: string): string =
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## Rust literal; the declared type annotation carries the width, so no suffix.
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case t.kind
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of ftStr:
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return "\"" & rustEscapeStringLit(value) & "\""
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else:
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return value
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