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+;; Feature identifiers for (cond-expand) and (features)
+
+;; R7RS Standard Feature Identifiers
+
+(id r7rs)
+(description "All R7RS Scheme implementations have this feature.")
+
+(id exact-closed)
+(description "The algebraic operations +, -, *, and expt where the second argument is a non-negative integer produce exactvalues given exact inputs.")
+
+(id exact-complex)
+(description "Exact complex numbers are provided.")
+
+(id ieee-float)
+(description "Inexact numbers are IEEE 754 binary floating point values.")
+
+(id full-unicode)
+(description "All Unicode characters present in Unicode version 6.0 are supported as Scheme characters.")
+
+(id ratios)
+(description "/ with exact arguments produces an exact result when the divisor is nonzero.")
+
+(id posix)
+(description "This implementation is running on a POSIX system.")
+
+(id windows)
+(description "This implementation is running on Windows.")
+
+(id unix)
+(description "Operating system flag")
+
+(id darwin)
+(description "Operating system flag")
+
+(id gnu-linux)
+(description "Operating system flag")
+
+(id bsd)
+(description "Operating system flag")
+
+(id freebsd)
+(description "Operating system flag")
+
+(id solaris)
+(description "Operating system flag")
+
+(id i386)
+(description "Running on a 32-bit Intel/AMD x86 processor.")
+
+(id x86-64)
+(description "Running on a 64-bit AMD/Intel x86 processor.")
+
+(id ppc)
+(description "Running on a PowerPC processor.")
+
+(id sparc)
+(description "Running on a Sun SPARC processor.")
+
+(id jvm)
+(description "Running on a Java Virtual Machine (JVM)")
+
+(id clr)
+(description "Running on a Common Language Runtime (.NET CLR)")
+
+(id llvm)
+(description "Running on the LLVM compiler infrastructure.")
+
+(id ilp32)
+(description "C language int, long and pointer types are all 32 bits wide.")
+
+(id lp64)
+(description "C language int type is 32 bits, long and pointer 64 bits wide.")
+
+(id ilp64)
+(description "C language int, long, and pointer types are all 64 its wide.")
+
+(id big-endian)
+(description "The CPU byte order is big-endian.")
+
+(id little-endian)
+(description "The CPU byte order is little-endian.")