Add feature support and K&R C conformance information

1 files changed, 84 insertions, 0 deletions

diff --git a/README b/README
index 17e5c18..f695e1a 100644
--- a/README
+++ b/README
@@ -22,3 +22,87 @@ Options:
                     added.
     --tree          Instead of compiling the file into assembly, show the parse
                     tree.
+
+Conformance with the K&R interpretation of C and feature support
+================================================================
+A2.2 Comments - unsupported by the parser, but the preprocessor removes them
+A2.5 Constants - integers (hexadecimal 0x1a, 0X1A, octal 07, decimal 1), signed
+            only Treating integers as unsigned is undefined. Unsupported:
+            floats, char, string literals.
+A4 Identifiers - functions, variables (int) are supported. struct, union are
+            not yet supported
+A4.1 Storage class - static is supported (actually, everything is static).
+            Automatic variables are unsupported.
+A4.2-A4.3 Types - supported: int; unsupported: char, enum, float, double,
+            struct, union, arrays, pointers
+A4.4 Type qualifiers - volatile won't be supported, const is unsupported
+A5 Objects and lvalues - not explicitly used, but assignment works
+A6 Conversions of operands - not supported since everything is treated as
+            signed int
+
+Expressions support
+-------------------
+precedence and associativity - supported by underlying library for parsing
+A7.1 Pointer generation - not tested/supported
+A7.2 Primary Expressions - identifiers, constants (int) are stored in a
+            register. String is unsupported
+A7.3 Postfix Expressions - unsupported
+function calls - supported, result is stored in register R0 (for int functions)
+            Other types (void) are not checked when using their value. If an
+            undefined function is used, it'll still try to branch to the label
+            Parameters are not supported.
+A7.4 Unary Operators - supported: ++ -- + - ~ ! Unsupported: sizeof & *
+A7.5 Casts - unsupported
+A7.6-A7.7, A7.9-7.13 - supported: * / % + - < > <= >= == != & ^ | Left to right
+A7.8 Shift - << >> is supported, if negative, no shift will be performed
+A7.14-A7.15 Logical AND && and OR || are supported. Result is indeed 0 or 1
+A7.16 Conditional operator ? : - supported
+A7.17 Assignment - supported: = Unsupported: *= /= %= += -= <<= >>= &= ^= |=
+            Supported for variable names only, pointers are not yet supported
+A7.18 Comma - supported
+A7.19 Constant expressions - not checked
+
+A8 Declarations
+A8.1 Storage class specifiers - unsupported
+A8.2 Type specifiers - unsupported, everything is assumed to be int. void in
+            the meaning of "no value" is not checked. Const is not meaningfully
+            supported yet
+A8.3 Structure and union declarations - unsupported
+A8.4 Enumerations - unsupported
+A8.5 Declarators - pointers and qualifiers are ignored, only a direct name is
+            supported
+A8.6 Meaning of declarators - pointer and array is unsupported, function is
+            supported without parameters and assumed to be an int function
+A8.7 Initialization - Supported for an expression resulting in an int
+A8.8 Type names - not verified
+A8.9 Typedef - won't be supported as we have int only
+A8.10 Type equivalence - not supported as everything is an int
+
+A9 Statements
+A9.1 Labeled statements - not supported
+A9.2 Expression statement - supported by parser
+A9.3 Compound statement - supported
+A9.4 Selection statements - if and if/else are supported, switch is not
+A9.5 Iteration statements - while, do/while and for are supported. A missing
+            second expression in the for is equivalent to a non-zero constant
+A9.6 Jump statements - goto is unsupported. continue, break are not supported
+            yet. return is supported with and without value. The function
+            result is undefined for the second case
+
+A10 External Declarations
+A10.1 Function Definitions - unsupported: extern static, parameters. Old style
+            parameter list is unsupported
+A10.2 External declarations - unsupported/unchecked
+
+A11 Scope and Linkage
+A11.1 Lexical scope - objects (variables), functions use the same namespace,
+            thereby not conforming to the Standard. Block scope is not
+            supported, everything is global
+A11.2 Linkage - not applicable / unsupported
+
+A12 Preprocessing
+Not supported by parser, use a dedicated preprocessor like cpp and enable
+removal of comments. Example: cpp -P file.c
+
+A13 Grammar
+Not checked
\ No newline at end of file