Add a LALR grammar for Rust with testing support

configure

@@ -647,6 +647,8 @@ probe CFG_ISCC             iscc
 probe CFG_JAVAC            javac
 probe CFG_ANTLR4           antlr4
 probe CFG_GRUN             grun
+probe CFG_FLEX             flex
+probe CFG_BISON            bison
 probe CFG_PANDOC           pandoc
 probe CFG_PDFLATEX         pdflatex
 probe CFG_XELATEX          xelatex

mk/grammar.mk

@@ -14,6 +14,11 @@ B = $(CFG_BUILD_DIR)/$(CFG_BUILD)/stage2/
 L = $(B)lib/rustlib/$(CFG_BUILD)/lib
 LD = $(CFG_BUILD)/stage2/lib/rustlib/$(CFG_BUILD)/lib/
 RUSTC = $(STAGE2_T_$(CFG_BUILD)_H_$(CFG_BUILD))
+ifeq ($(CFG_OSTYPE),apple-darwin)
+	FLEX_LDFLAGS=-ll
+else
+	FLEX_LDFLAGS=-lfl
+endif
 
 # Run the reference lexer against libsyntax and compare the tokens and spans.
 # If "// ignore-lexer-test" is present in the file, it will be ignored.
@@ -67,3 +72,46 @@ $(info cfg: javac not available, skipping lexer test...)
 check-lexer:
 
 endif
+
+$(BG)lex.yy.c: $(SG)lexer.l $(BG)
+	@$(call E, flex: $@)
+	$(Q)$(CFG_FLEX) -o $@ $<
+
+$(BG)lexer-lalr.o: $(BG)lex.yy.c $(BG)parser-lalr.tab.h
+	@$(call E, cc: $@)
+	$(Q)$(CFG_CC) -include $(BG)parser-lalr.tab.h -c -o $@ $<
+
+$(BG)parser-lalr.tab.c $(BG)parser-lalr.tab.h: $(SG)parser-lalr.y
+	@$(call E, bison: $@)
+	$(Q)$(CFG_BISON) $< --output=$(BG)parser-lalr.tab.c --defines=$(BG)parser-lalr.tab.h \
+		--name-prefix=rs --warnings=error=all
+
+$(BG)parser-lalr.o: $(BG)parser-lalr.tab.c
+	@$(call E, cc: $@)
+	$(Q)$(CFG_CC) -c -o $@ $<
+
+$(BG)parser-lalr-main.o: $(SG)parser-lalr-main.c
+	@$(call E, cc: $@)
+	$(Q)$(CFG_CC) -std=c99 -c -o $@ $<
+
+$(BG)parser-lalr: $(BG)parser-lalr.o $(BG)parser-lalr-main.o $(BG)lexer-lalr.o
+	@$(call E, cc: $@)
+	$(Q)$(CFG_CC) -o $@ $^ $(FLEX_LDFLAGS)
+
+
+ifdef CFG_FLEX
+ifdef CFG_BISON
+check-grammar: $(BG) $(BG)parser-lalr
+	$(info Verifying grammar ...)
+	$(SG)testparser.py -p $(BG)parser-lalr -s $(S)src
+
+else
+$(info cfg: bison not available, skipping parser test...)
+check-grammar:
+
+endif
+else
+$(info cfg: flex not available, skipping parser test...)
+check-grammar:
+
+endif